To return for a moment to the Glacial period. You might have asked Dawson whether ibex, marmot, etc., etc., were carried from mountain to mountain in Europe on floating ice; and whether musk ox got to England on icebergs? Yet England has subsided, if we trust to the good evidence of shells alone, more during Glacial period than America is known to have done.

For Heaven's sake instil a word of caution into Tyndall's ears. I saw an extract that valleys of Switzerland were wholly due to glaciers. He cannot have reflected on valleys in tropical countries. The grandest valleys I ever saw were in Tahiti. Again, if I understand, he supposes that glaciers wear down whole mountain ranges; thus lower their height, decrease the temperature, and decrease the glaciers themselves. Does he suppose the whole of Scotland thus worn down? Surely he must forget oscillation of level would be more potent one way or another during such enormous lapses of time. It would be hard to believe any mountain range has been so long stationary.

I suppose Lyell's book will soon be out. (358/2. "The Antiquity of Man," 1863.) I was very glad to see in a newspaper that Murray sold 4,000. What a sale!

I am now working on cultivated plants, and rather like my work; but I am horribly afraid I make the rashest remarks on value of differences. I trust to a sort of instinct, and, God knows, can seldom give any reason for my remarks. Lord, in what a medley the origin of cultivated plants is. I have been reading on strawberries, and I can find hardly two botanists agree what are the wild forms; but I pick out of horticultural books here and there queer cases of variation, inheritance, etc., etc.

What a long letter I have scribbled; but you must forgive me, for it is a great pleasure thus talking to you.

Did you ever hear of "Condy's Ozonised Water"? I have been trying it with, I think, extraordinary advantage—to comfort, at least. A teaspoon, in water, three or four times a day. If you meet any poor dyspeptic devil like me, suggest it.

LETTER 359. TO J.D. HOOKER. Down, 26th [March 1863].

I hope and think you are too severe on Lyell's early chapters. Though so condensed, and not well arranged, they seemed to me to convey with uncommon force the antiquity of man, and that was his object. (359/1. "The Geological Evidences of the Antiquity of Man": London, 1863.) It did not occur to me, but I fear there is some truth in your criticism, that nothing is to be trusted until he [Lyell] had observed it.

I am glad to see you stirred up about tropical plants during Glacial period.

Remember that I have many times sworn to you that they coexisted; so, my dear fellow, you must make them coexist. I do not think that greater coolness in a disturbed condition of things would be required than the zone of the Himalaya, in which you describe some tropical and temperate forms commingling (359/2. "During this [the Glacial period], the coldest point, the lowlands under the equator, must have been clothed with a mingled tropical and temperate vegetation, like that described by Hooker as growing luxuriantly at the height of from four to five thousand feet on the lower slopes of the Himalaya, but with perhaps a still greater preponderance of temperate forms" ("Origin of Species," Edition VI., page 338).); and as in the lower part of the Cameroons, and as Seemann describes, in low mountains of Panama. It is, as you say, absurd to suppose that such a genus as Dipterocarpus (359/3. Dipterocarpus, a genus of the Dipterocarpaceae, a family of dicotyledonous plants restricted to the tropics of the Old World.) could have been developed since the Glacial era; but do you feel so sure, as to oppose (359/4. The meaning seems to be: "Do you feel so sure that you can bring in opposition a large body of considerations to show, etc.") a large body of considerations on the other side, that this genus could not have been slowly accustomed to a cooler climate? I see Lindley says it has not been brought to England, and so could not have been tried in the greenhouse. Have you materials to show to what little height it ever ascends the mountains of Java or Sumatra? It makes a mighty difference, the whole area being cooled; and the area perhaps not being in all respects, such as dampness, etc., etc., fitted for such temperate plants as could get in. But, anyhow, I am ready to swear again that Dipterocarpus and any other genus you like to name did survive during a cooler period.

About reversion you express just what I mean. I somehow blundered, and mentally took literally that the child inherited from his grandfather. This view of latency collates a lot of facts—secondary sexual characters in each individual; tendency of latent character to appear temporarily in youth; effect of crossing in educing talent, character, etc. When one thinks of a latent character being handed down, hidden for a thousand or ten thousand generations, and then suddenly appearing, one is quite bewildered at the host of characters written in invisible ink on the germ. I have no evidence of the reversion of all characters in a variety. I quite agree to what you say about genius. I told Lyell that passage made me groan.

What a pity about Falconer! (359/5. This refers to Falconer's claim of priority against Lyell. See "Life and Letters," III., page 14; also Letters 166 and 168.) How singular and how lamentable!

Remember orchid pods. I have a passion to grow the seeds (and other motives). I have not a fact to go on, but have a notion (no, I have a firm conviction!) that they are parasitic in early youth on cryptogams! (359/6. In an article on British Epiphytal Orchids ("Gard. Chron." 1884, page 144) Malaxis paludosa is described by F.W. Burbidge as being a true epiphyte on the stems of Sphagnum. Stahl states that the difficulty of cultivating orchids largely depends on their dependence on a mycorhizal fungus,—though he does not apply his view to germination. See Pringsheim's "Jahrbucher," XXXIV., page 581. We are indebted to Sir Joseph Hooker for the reference to Burbidge's paper.) Here is a fool's notion. I have some planted on Sphagnum. Do any tropical lichens or mosses, or European, withstand heat, or grow on any trees in hothouse at Kew? If so, for love of Heaven, favour my madness, and have some scraped off and sent me.

I am like a gambler, and love a wild experiment. It gives me great pleasure to fancy that I see radicles of orchid seed penetrating the Sphagnum. I know I shall not, and therefore shall not be disappointed.

LETTER 360. TO J.D. HOOKER. Down [September 26th 1863].

...About New Zealand, at last I am coming round, and admit it must have been connected with some terra firma, but I will die rather than admit Australia. How I wish mountains of New Caledonia were well worked!...

LETTER 361. TO J.D. HOOKER.

(361/1. In the earlier part of this letter Mr. Darwin refers to a review on Planchon in the "Nat. History Review," April 1865. There can be no doubt, therefore, that "Thomson's article" must be the review of Jordan's "Diagnoses d'especes nouvelles ou meconnues," etc., in the same number, page 226. It deals with "lumpers" and "splitters," and a possible trinomial nomenclature.)

April 17th [1865].

I have been very much struck by Thomson's article; it seems to me quite remarkable for its judgment, force, and clearness. It has interested me greatly. I have sometimes loosely speculated on what nomenclature would come to, and concluded that it would be trinomial. What a name a plant will formally bear with the author's name after genus (as some recommend), and after species and subspecies! It really seems one of the greatest questions which can be discussed for systematic Natural History. How impartially Thomson adjusts the claims of "hair-splitters" and "lumpers"! I sincerely hope he will pretty often write reviews or essays. It is an old subject of grief to me, formerly in Geology and of late in Zoology and Botany, that the very best men (excepting those who have to write principles and elements, etc.) read so little, and give up nearly their whole time to original work. I have often thought that science would progress more if there was more reading. How few read any long and laborious papers! The only use of publishing such seems to be as a proof that the author has given time and labour to his work.

LETTER 362. TO J.D. HOOKER. Down, October 22nd and 28th, 1865.

As for the anthropologists being a bete noire to scientific men, I am not surprised, for I have just skimmed through the last "Anthrop. Journal," and it shows, especially the long attack on the British Association, a curious spirit of insolence, conceit, dullness, and vulgarity. I have read with uncommon interest Travers' short paper on the Chatham Islands. (362/1. See Travers, H.H., "Notes on the Chatham Islands," "Linn. Soc. Journ." IX., October 1865. Mr. Travers says he picked up a seed of Edwardsia, evidently washed ashore. The stranded logs indicated a current from New Zealand.) I remember your pitching into me with terrible ferocity because I said I thought the seed of Edwardsia might have been floated from Chili to New Zealand: now what do you say, my young man, to the three young trees of the same size on one spot alone of the island, and with the cast-up pod on the shore? If it were not for those unlucky wingless birds I could believe that the group had been colonised by accidental means; but, as it is, it appears by far to me the best evidence of continental extension ever observed. The distance, I see, is 360 miles. I wish I knew whether the sea was deeper than between New Zealand and Australia. I fear you will not admit such a small accident as the wingless birds having been transported on icebergs. Do suggest, if you have a chance, to any one visiting the Islands again, to look out for erratic boulders there. How curious his statement is about the fruit-trees and bees! (362/2. "Since the importation of bees, European fruit-trees and bushes have produced freely." Travers, "Linn. Soc. Journal," IX., page 144.) I wish I knew whether the clover had spread before the bees were introduced...

I saw in the "Gardeners' Chronicle" the sentence about the "Origin" dying in Germany, but did not know it was by Seemann.

LETTER 363. TO C. LYELL. Down, February 7th [1866].

I am very much obliged for your note and the extract, which have interested me extremely. I cannot disbelieve for a moment Agassiz on Glacial action after all his experience, as you say, and after that capital book with plates which he early published (363/1. "Etudes sur les Glaciers"; Neuchatel, 1840.); as for his inferences and reasoning on the valley of the Amazon that is quite another question, nor can he have seen all the regions to which Mrs. A. alludes. (363/2. A letter from Mrs. Agassiz to Lady Lyell, which had been forwarded to Mr. Darwin. The same letter was sent also to Sir Charles Bunbury, who, in writing to Lyell on February 3rd, 1866, criticises some of the statements. He speaks of Agassiz's observations on glacial phenomena in Brazil as "very astonishing indeed; so astonishing that I have very great difficulty in believing them. They shake my faith in the glacial system altogether; or perhaps they ought rather to shake the faith in Agassiz...If Brazil was ever covered with glaciers, I can see no reason why the whole earth should not have been so. Perhaps the whole terrestrial globe was once 'one entire and perfect icicle.'" (From the privately printed "Life" of Sir Charles Bunbury, edited by Lady Bunbury, Volume ii., page 334).) Her letter is not very clear to me, and I do not understand what she means by "to a height of more than three thousand feet." There are no erratic boulders (to which I particularly attended ) in the low country round Rio. It is possible or even probable that this area may have subsided, for I could detect no evidence of elevation, or any Tertiary formations or volcanic action. The Organ Mountains are from six to seven thousand feet in height; and I am only a little surprised at their bearing the marks of glacial action. For some temperate genera of plants, viz., Vaccinium, Andromeda, Gaultheria, Hypericum, Drosera, Habenaria, inhabit these mountains, and I look at this almost as good evidence of a cold period, as glacial action. That there are not more temperate plants can be accounted for by the isolated position of these mountains. There are no erratic boulders on the Pacific coast north of Chiloe, and but few glaciers in the Cordillera, but it by no means follows, I think, that there may not have been formerly gigantic glaciers on the eastern and more humid side.

In the third edition of "Origin," page 403 (363/3. "Origin," Edition VI., page 335, 1882. "Mr. D. Forbes informs me that he found in various parts of the Cordillera, from lat. 13 deg W. to 30 deg S., at about the height of twelve thousand feet, deeply furrowed rocks...and likewise great masses of detritus, including grooved pebbles. Along this whole space of the Cordillera true glaciers do not now exist, even at much more considerable height. "), you will find a brief allusion, on authority of Mr. D. Forbes, on the former much lower extension of glaciers in the equatorial Cordillera. Pray also look at page 407 at what I say on the nature of tropical vegetation (which I could now much improve) during the Glacial period. (363/4. "During this, the coldest period, the lowlands under the Equator must have been clothed with a mingled tropical and temperate vegetation..." ("Origin," Edition VI., 1882, page 338).)

I feel a strong conviction that soon every one will believe that the whole world was cooler during the Glacial period. Remember Hooker's wonderful case recently discovered of the identity of so many temperate plants on the summit of Fernando Po, and on the mountains of Abyssinia. (363/5. "Dr. Hooker has also lately shown that several of the plants living in the upper parts of the lofty island of Fernando Po, and in the neighbouring Cameroon Mountains, in the Gulf of Guinea, are closely related to those on the mountains of Abyssinia, and likewise to those of temperate Europe" (loc. cit., page 337).) I look at [it] as certain that these plants crossed the whole of Africa from east to west during the same period. I wish I had published a long chapter written in full, and almost ready for the press, on this subject, which I wrote ten years ago. It was impossible in the "Origin" to give a fair abstract.

My health is considerably improved, so that I am able to work nearly two hours a day, and so make some little progress with my everlasting book on domestic varieties. You will have heard of my sister Catherine's easy death last Friday morning. (363/6. Catherine Darwin died in February 1866.) She suffered much, and we all look at her death as a blessing, for there was much fear of prolonged and greater suffering. We are uneasy about Susan, but she has hitherto borne it better than we could have hoped. (363/7. Susan Darwin died in October 1866.)

Remember glacial action of Lebanon when you speak of no glacial action in S. on Himalaya, and in S.E. Australia.

P.S.—I have been very glad to see Sir C. Bunbury's letter. (363/8. The letter from Bunbury to Lyell, already quoted on this subject. Bunbury writes: "There is nothing in the least NORTHERN, nothing that is not characteristically Brazilian, in the flora of the Organ Mountains.") If the genera which I name from Gardner (363/9. "Travels in the Interior of Brazil," by G. Gardner: London, 1846.) are not considered by him as usually temperate forms, I am, of course, silenced; but Hooker looked over the MS. chapter some ten years ago and did not score out my remarks on them, and he is generally ready enough to pitch into my ignorance and snub me, as I often deserve. My wonder was how any, ever so few, temperate forms reached the mountains of Brazil; and I supposed they travelled by the rather high land and ranges (name forgotten) which stretch from the Cordillera towards Brazil. Cordillera genera of plants have also, somehow, reached the Silla of Caracas. When I think of the vegetation of New Zealand and west coast of South America, where glaciers now descend to or very near to the sea, I feel it rash to conclude that all tropical forms would be destroyed by a considerably cooler period under the Equator.

LETTER 364. TO C. LYELL. Down, Thursday, February 15th [1866].

Many thanks for Hooker's letter; it is a real pleasure to me to read his letters; they are always written with such spirit. I quite agree that Agassiz could never mistake weathered blocks and glacial action; though the mistake has, I know, been made in two or three quarters of the world. I have often fought with Hooker about the physicists putting their veto on the world having been cooler; it seems to me as irrational as if, when geologists first brought forward some evidence of elevation and subsidence, a former Hooker had declared that this could not possibly be admitted until geologists could explain what made the earth rise and fall. It seems that I erred greatly about some of the plants on the Organ Mountains. (364/1. "On the Organ Mountains of Brazil some few temperate European, some Antarctic, and some Andean genera were found by Gardner, which did not exist in the low intervening hot countries" ("Origin," Edition VI., page 336).) But I am very glad to hear about Fuchsia, etc. I cannot make out what Hooker does believe; he seems to admit the former cooler climate, and almost in the same breath to spurn the idea. To retort Hooker's words, "it is inexplicable to me" how he can compare the transport of seeds from the Andes to the Organ Mountains with that from a continent to an island. Not to mention the much greater distance, there are no currents of water from one to the other; and what on earth should make a bird fly that distance without resting many times? I do not at all suppose that nearly all tropical forms were exterminated during the cool period; but in somewhat depopulated areas, into which there could be no migration, probably many closely allied species will have been formed since this period. Hooker's paper in the "Natural History Review" (364/2. Possibly an unsigned article, entitled "New Colonial Floras" (a review of Grisebach's "Flora of the British West Indian Islands" and Thwaites' "Enumeratio Plantarum Zeylaniae").—"Nat. Hist. Review," January 1865, page 46. See Letter 184.) is well worth studying; but I cannot remember that he gives good grounds for his conviction that certain orders of plants could not withstand a rather cooler climate, even if it came on most gradually. We have only just learnt under how cool a temperature several tropical orchids can flourish. I clearly saw Hooker's difficulty about the preservation of tropical forms during the cool period, and tried my best to retain one spot after another as a hothouse for their preservation; but it would not hold good, and it was a mere piece of truckling on my part when I suggested that longitudinal belts of the world were cooled one after the other. I shall very much like to see Agassiz's letter, whenever you receive one. I have written a long letter; but a squabble with or about Hooker always does me a world of good, and we have been at it many a long year. I cannot understand whether he attacks me as a wriggler or a hammerer, but I am very sure that a deal of wriggling has to be done.

LETTER 365. TO J.D. HOOKER. Down, July 30th [1866].

Many thanks about the lupin. Your letter has interested me extremely, and reminds me of old times. I suppose, by your writing, you would like to hear my notions. I cannot admit the Atlantis connecting Madeira and Canary Islands without the strongest evidence, and all on that side (365/1. Sir J.D. Hooker lectured on "Insular Floras" at the Nottingham meeting of the British Association on August 27th, 1866. His lecture is given in the "Gardeners' Chronicle," 1867, page 6. No doubt he was at this time preparing his remarks on continental extension, which take the form of a judicial statement, giving the arguments and difficulties on both sides. He sums up against continental extension, which, he says, accounts for everything and explains nothing; "whilst the hypothesis of trans-oceanic migration, though it leaves a multitude of facts unexplained, offers a rational solution of many of the most puzzling phenomena." In his lecture, Sir Joseph wrote that in ascending the mountains in Madeira there is but little replacement of lowland species by those of a higher northern latitude. "Plants become fewer and fewer as we ascend, and their places are not taken by boreal ones, or by but very few."): the depth is so great; there is nothing geologically in the islands favouring the belief; there are no endemic mammals or batrachians. Did not Bunbury show that some Orders of plants were singularly deficient? But I rely chiefly on the large amount of specific distinction in the insects and land-shells of P. Santo and Madeira: surely Canary and Madeira could not have been connected, if Madeira and P. Santo had long been distinct. If you admit Atlantis, I think you are bound to admit or explain the difficulties.

With respect to cold temperate plants in Madeira, I, of course, know not enough to form an opinion; but, admitting Atlantis, I can see their rarity is a great difficulty; otherwise, seeing that the latitude is only a little north of the Persian Gulf, and seeing the long sea-transport for seeds, the rarity of northern plants does not seem to me difficult. The immigration may have been from a southerly direction, and it seems that some few African as well as coldish plants are common to the mountains to the south.

Believing in occasional transport, I cannot feel so much surprise at there being a good deal in common to Madeira and Canary, these being the nearest points of land to each other. It is quite new and very interesting to me what you say about the endemic plants being in so large a proportion rare species. From the greater size of the workshop (i.e., greater competition and greater number of individuals, etc.) I should expect that continental forms, as they are occasionally introduced, would always tend to beat the insular forms; and, as in every area, there will always be many forms more or less rare tending towards extinction, I should certainly have expected that in islands a large proportion of the rarer forms would have been insular in their origin. The longer the time any form has existed in an island into which continental forms are occasionally introduced, by so much the chances will be in favour of its being peculiar or abnormal in nature, and at the same time scanty in numbers. The duration of its existence will also have formerly given it the best chance, when it was not so rare, of being widely distributed to adjoining archipelagoes. Here is a wriggle: the older a form is, the better the chance will be of its having become developed into a tree! An island from being surrounded by the sea will prevent free immigration and competition, hence a greater number of ancient forms will survive on an island than on the nearest continent whence the island was stocked; and I have always looked at Clethra (365/2. Clethra is an American shrubby genus of Ericaceae, found nowhere nearer to Madeira than North America. Of this plant and of Persea, Sir Charles Lyell ("Principles," 1872, Volume II., page 422) says: "Regarded as relics of a Miocene flora, they are just such forms as we should naturally expect to have come from the adjoining Miocene continent." See also "Origin of Species," Edition VI., page 83, where a similar view is quoted from Heer.) and the other extra-European forms as remnants of the Tertiary flora which formerly inhabited Europe. This preservation of ancient forms in islands appears to me like the preservation of ganoid fishes in our present freshwaters. You speak of no northern plants on mountains south of the Pyrenees: does my memory quite deceive me that Boissier published a long list from the mountains in Southern Spain? I have not seen Wollaston's, "Catalogue," (365/4. Probably the "Catalogue of the Coleopterous Insects of the Canaries in the British Museum," 1864.) but must buy it, if it gives the facts about rare plants which you mention.

And now I have given more than enough of my notions, which I well know will be in flat contradiction with all yours.

Wollaston, in his "Insecta Maderensia" (365/5. "Insecta Maderensia," London, 1854.), 4to, page 12, and in his "Variation of Species," pages 82-7, gives the case of apterous insects, but I remember I worked out some additional details.

I think he gives in these same works the proportion of European insects.

LETTER 366. TO J.D. HOOKER.

(366/1. Sir Joseph had asked (July 31st, 1866): "Is there an evidence that the south of England and of Ireland were not submerged during the Glacial epoch, when the W. and N. of England were islands in a glacial sea? And supposing they were above water, could the present Atlantic and N.W. of France floras we now find there have been there during the Glacial epoch?—Yet this is what Forbes demands, page 346. At page 347 he sees this objection, and wriggles out of his difficulty by putting the date of the Channel 'towards the close of the Glacial epoch.' What does Austen make the date of the Channel?—ante or post Glacial?" The changes in level and other questions are dealt with in a paper by R.A.C. Austen (afterwards Godwin-Austen), "On the Superficial Accumulations of the Coasts of the English Channel and the Changes they indicate." "Quart. Journ. Geol. Soc." VII., 1851, page 118. Obit. notice by Prof. Bonney in the "Proc. Geol. Soc." XLI., page 37, 1885.)

Down, August 3rd [1866].

I will take your letter seriatim. There is good evidence that S.E. England was dry land during the Glacial period. I forget what Austen says, but Mammals prove, I think, that England has been united to the Continent since the Glacial period. I don't see your difficulty about what I say on the breaking of an isthmus: if Panama was broken through would not the fauna of the Pacific flow into the W. Indies, or vice versa, and destroy a multitude of creatures? Of course I'm no judge, but I thought De Candolle had made out his case about small areas of trees. You will find at page 112, 3rd edition "Origin," a too concise allusion to the Madeira flora being a remnant of the Tertiary European flora. I shall feel deeply interested by reading your botanical difficulties against occasional immigration. The facts you give about certain plants, such as the heaths, are certainly very curious. (366/2. In Hooker's lecture he gives St. Dabeoc's Heath and Calluna vulgaris as the most striking of the few boreal plants in the Azores. Darwin seems to have been impressed by the boreal character of the Azores, thus taking the opposite view to that of Sir Joseph. See Letter 370, note.) I thought the Azores flora was more boreal, but what can you mean by saying that the Azores are nearer to Britain and Newfoundland than to Madeira?—on the globe they are nearly twice as far off. (366/3. See Letter 368.) With respect to sea currents, I formerly made enquiries at Madeira, but cannot now give you the results; but I remember that the facts were different from what is generally stated: I think that a ship wrecked on the Canary Islands was thrown up on the coast of Madeira.

You speak as if only land-shells differed in Madeira and Porto Santo: does my memory deceive me that there is a host of representative insects?

When you exorcise at Nottingham occasional means of transport, be honest, and admit how little is known on the subject. Remember how recently you and others thought that salt water would soon kill seeds. Reflect that there is not a coral islet in the ocean which is not pretty well clothed with plants, and the fewness of the species can hardly with justice be attributed to the arrival of few seeds, for coral islets close to other land support only the same limited vegetation. Remember that no one knew that seeds would remain for many hours in the crops of birds and retain their vitality; that fish eat seeds, and that when the fish are devoured by birds the seeds can germinate, etc. Remember that every year many birds are blown to Madeira and to the Bermudas. Remember that dust is blown 1,000 miles over the Atlantic. Now, bearing all this in mind, would it not be a prodigy if an unstocked island did not in the course of ages receive colonists from coasts whence the currents flow, trees are drifted and birds are driven by gales. The objections to islands being thus stocked are, as far as I understand, that certain species and genera have been more freely introduced, and others less freely than might have been expected. But then the sea kills some sorts of seeds, others are killed by the digestion of birds, and some would be more liable than others to adhere to birds' feet. But we know so very little on these points that it seems to me that we cannot at all tell what forms would probably be introduced and what would not. I do not for a moment pretend that these means of introduction can be proved to have acted; but they seem to me sufficient, with no valid or heavy objections, whilst there are, as it seems to me, the heaviest objections on geological and on geographical distribution grounds (pages 387, 388, "Origin" (366/4. Edition III., or Edition VI., page 323.) to Forbes' enormous continental extensions. But I fear that I shall and have bored you.

LETTER 367. J.D. HOOKER TO CHARLES DARWIN.

(367/1. In a letter of July 31st, Sir J.D. Hooker wrote, "You must not suppose me to be a champion of continental connection, because I am not agreeable to trans-oceanic migration...either hypothesis appears to me well to cover the facts of oceanic floras, but there are grave objections to both, botanical to yours, geological to Forbes'.")

The following interesting letters give some of Sir Joseph's difficulties.)

Kew, August 4th, 1866.

You mention ("Journal") no land-birds, except introduced, upon St. Helena. Beatson (Introduction xvii) mentions one (367/2. Aegialitis sanctae-helenae, a small plover "very closely allied to a species found in South Africa, but presenting certain differences which entitle it to the rank of a peculiar species" (Wallace, "Island Life," page 294). In the earlier editions of the "Origin" (e.g. Edition III., page 422) Darwin wrote that "Madeira does not possess one peculiar bird." In Edition IV., 1866, page 465, the mistake was put right.) "in considerable numbers," resembles sand-lark—is called "wire bird," has long greenish legs like wires, runs fast, eyes large, bill moderately long, is rather shy, does not possess much powers of flight. What was it? I have written to ask Sclater, also about birds of Madeira and Azores. It is a very curious thing that the Azores do not contain the (non-European) American genus Clethra, that is found in Madeira and Canaries, and that the Azores contain no trace of American element (beyond what is common to Madeira), except a species of Sanicula, a genus with hooked bristles to the small seed-vessels. The European Sanicula roams from Norway to Madeira, Canaries, Cape Verde, Cameroons, Cape of Good Hope, and from Britain to Japan, and also is, I think, in N. America; but does not occur in the Azores, where it is replaced by one that is of a decidedly American type.

This tells heavily against the doctrine that joins Atlantis to America, and is much against your trans-oceanic migration—for considering how near the Azores are to America, and in the influence of the Gulf-stream and prevalent winds, it certainly appears marvellous. Not only are the Azores in a current that sweeps the coast of U. States, but they are in the S.W. winds, and in the eye of the S.W. hurricanes!

I suppose you will answer that the European forms are prepotent, but this is riding prepotency to death.

R.T. Lowe has written me a capital letter on the Madeiran, Canarian, and Cape Verde floras.

I misled you if I gave you to understand that Wollaston's Catalogue said anything about rare plants. I am worked and worried to death with this lecture: and curse myself as a soft headed and hearted imbecile to have accepted it.

LETTER 368. J.D. HOOKER TO CHARLES DARWIN. Kew, Monday [August 6th, 1866].

Again thanks for your letter. You need not fear my not doing justice to your objections to the continental hypothesis!

Referring to page 344 again (368/1. "Origin of Species," Edition III., pages 343-4: "In some cases, however, as by the breaking of an isthmus and the consequent irruption of a multitude of new inhabitants, or by the final subsidence of an island, the extinction may have been comparatively rapid."), it never occurred to me that you alluded to extinction of marine life: an isthmus is a piece of land, and you go on in the same sentence about "an island," which quite threw me out, for the destruction of an isthmus makes an island!

I surely did not say Azores nearer to Britain and Newfoundland "than to Madeira," but "than Madeira is to said places."

With regard to the Madeiran coleoptera I rely very little on local distribution of insects—they are so local themselves. A butterfly is a great rarity in Kew, even a white, though we are surrounded by market gardens. All insects are most rare with us, even the kinds that abound on the opposite side of Thames.

So with shells, we have literally none—not a Helix even, though they abound in the lanes 200 yards off the Gardens. Of the 89 Dezertas insects [only?] 11 are peculiar. Of the 162 Porto Santan 113 are Madeiran and 51 Dezertan.

Never mind bothering Murray about the new edition of the "Origin" for me. You will tell me anything bearing on my subject.

LETTER 369. J.D. HOOKER TO CHARLES DARWIN. Kew, August 7th, 1866.

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. I must get to the bottom of this question, and that is all I can do. Some cleverer fellow one day will knock the bottom out of it, and 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, and I cannot accept a hypothesis that leaves so many facts unaccounted for. You say the temperate parts of N. America [are] nearly two and a half times as distant from the Azores as Europe is. According to a rough calculation on Col. James' chart I make E. Azores to Portugal 850, West do. to Newfoundland 1500, but I am writing to a friend at Admiralty to have the distance calculated (which looks like cracking nuts with Nasmyth's hammer!)

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.

I do want to sum up impartially, leaving the 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), and now Andrew Murray. I do not regard all these, and 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 favourable to you...How I do yearn to go out again to St. Helena.

Of course I accept the ornithological evidence as tremendously strong, though why they should get blown westerly, and not change specifically, as insects, shells, and plants have done, is a mystery.

LETTER 370. TO J.D. HOOKER. Down, August 8th [1866].

It would be a very great pleasure to me if I could think that my letters were of the least use to you. I must have expressed myself badly for you to suppose that I look at islands being stocked by occasional transport as a well-established hypothesis. We both give up creation, and therefore have to account for the inhabitants of islands either by continental extensions or by occasional transport. Now, all that I maintain is that of these two alternatives, one of which must be admitted, notwithstanding very many difficulties, occasional transport is by far the most probable. I go thus far further—that I maintain, knowing what we do, that it would be inexplicable if unstocked islands were not stocked to a certain extent at least by these occasional means. European birds are occasionally driven to America, but far more rarely than in the reverse direction: they arrive via Greenland (Baird); yet a European lark has been caught in Bermuda.

By the way, you might like to hear that European birds regularly migrate via the northern islands to Greenland.

About the erratics in the Azores see "Origin," page 393. (370/1. "Origin," Edition VI., page 328. The importance of erratic blocks on the Azores is in showing the probability of ice-borne seeds having stocked the islands, and thus accounting for the number of European species and their unexpectedly northern character. Darwin's delight in the verification of his theory is described in a letter to Sir Joseph of April 26th, 1858, in the "Life and Letters," II., page 112.) Hartung could hardly be mistaken about granite blocks on a volcanic island.

I do not think it a mystery that birds have not been modified in Madeira. (370/2. "Origin," Edition VI., page 328. Madeira has only one endemic bird. Darwin accounts for the fact from the island having been stocked with birds which had struggled together and become mutually co-adapted on the neighbouring continents. "Hence, when settled in their new homes, each kind will have been kept by the others in its proper place and habits, and will consequently have been but little liable to modification." Crossing with frequently arriving immigrants will also tend to keep down modification.) Pray look at page 422 of "Origin" [Edition III.]. You would not think it a mystery if you had seen the long lists which I have (somewhere) of the birds annually blown, even in flocks, to Madeira. The crossed stock would be the more vigorous.

Remember if you do not come here before Nottingham, if you do not come afterwards I shall think myself diabolically ill-used.

LETTER 371. J.D. HOOKER TO CHARLES DARWIN. Kew, August 9th, 1866.

If my letters did not gene you it is impossible that you should suppose that yours were of no use to me! I would throw up the whole thing were it not for correspondence with you, which is the only bit of silver in the affair. I do feel it disgusting to have to make a point of a speciality in which I cannot see my way a bit further than I could before I began. To be sure, I have a very much clearer notion of the pros and cons on both sides (though these were rather forgotten facts than rediscoveries). I see the sides of the well further down more distinctly, but the bottom is as obscure as ever.

I think I know the "Origin" by heart in relation to the subject, and it was reading it that suggested the queries about Azores boulders and Madeira birds. The former you and I have talked over, and I thought I remembered that you wanted it confirmed. The latter strikes me thus: why should plants and insects have been so extensively changed and birds not at all? I perfectly understand and feel the force of your argument in reference to birds per se, but why do these not apply to insects and plants? Can you not see that this suggests the conclusion that the plants are derived one way and the birds another?

I certainly did take it for granted that you supposed the stocking [by] occasional transport to be something even more than a "well-established hypothesis," but disputants seldom stop to measure the strength of their antagonist's opinion.

I shall be with you on Saturday week, I hope. I should have come before, but have made so little progress that I could not. I am now at St. Helena, and shall then go to, and finish with, Kerguelen's land.

(371/1. After giving the distances of the Azores, etc., from America, Sir Joseph continues:—)

But to my mind [it] does not mend the matter—for I do not ask why Azores have even proportionally (to distance) a smaller number of American plants, but why they have none, seeing the winds and currents set that way. The Bermudas are all American in flora, but from what Col. Munro informs me I should say they have nothing but common American weeds and the juniper (cedar). No changed forms, yet they are as far from America as Azores from Europe. I suppose they are modern and out of the pale.

...There is this, to me, astounding difference between certain oceanic islands which were stocked by continental extension and those stocked by immigration (following in both definitions your opinion), that the former [continental] do contain many types of the more distant continent, the latter do not any! Take Madagascar, with its many Asiatic genera unknown in Africa; Ceylon, with many Malayan types not Peninsular; Japan, with many non-Asiatic American types. Baird's fact of Greenland migration I was aware of since I wrote my Arctic paper. I wish I was as satisfied either of continental [extensions] or of transport means as I am of my Greenland hypothesis!

Oh, dear me, what a comfort it is to have a belief (sneer away).

LETTER 372. J.D. HOOKER TO CHARLES DARWIN. Kew, December 4th, 1866.

I have just finished the New Zealand "Manual" (372/1. "Handbook of the New Zealand Flora."), and am thinking about a discussion on the geographical distribution, etc., of the plants. There is scarcely a single indigenous annual plant in the group. I wish that I knew more of the past condition of the islands, and whether they have been rising or sinking. There is much that suggests the idea that the islands were once connected during a warmer epoch, were afterwards separated and much reduced in area to what they now are, and lastly have assumed their present size. The remarkable general uniformity of the flora, even of the arboreous flora, throughout so many degrees of latitude, is a very remarkable feature, as is the representation of a good many of the southern half of certain species of the north, by very closely allied varieties or species; and, lastly, there is the immense preponderance of certain genera whose species all run into one another and vary horribly, and which suggest a rising area. I hear that a whale has been found some miles inland.

LETTER 373. J.D. HOOKER TO CHARLES DARWIN. Kew, December 14th, 1866.

I do not see how the mountains of New Zealand, S. Australia, and Tasmania could have been peopled, and [with] so large an extent of antarctic (373/1. "Introductory Essay to Flora of New Zealand," page xx. "The plants of the Antarctic islands, which are equally natives of New Zealand, Tasmania, and Australia, are almost invariably found only on the lofty mountains of these countries.") forms common to Fuegia, without some intercommunication. And I have always supposed this was before the immigration of Asiatic plants into Australia, and of which plants the temperate and tropical plants of that country may be considered as altered forms. The presence of so many of these temperate and cold Australian and New Zealand genera on the top of Kini Balu in Borneo (under the equator) is an awful staggerer, and demands a very extended northern distribution of Australian temperate forms. It is a frightful assumption that the plains of Borneo were covered with a temperate cold vegetation that was driven up Kini Balu by the returning cold. Then there is the very distant distribution of a few Australian types northward to the Philippines, China, and Japan: that is a fearful and wonderful fact, though, as these plants are New Zealand too for the most part, the migration northward may have been east of Australia.

LETTER 374. TO J.D. HOOKER. December 24th [1866].

...One word more about the flora derived from supposed Pleistocene antarctic land requiring land intercommunication. This will depend much, as it seems to me, upon how far you finally settle whether Azores, Cape de Verdes, Tristan d'Acunha, Galapagos, Juan Fernandez, etc., etc., etc., have all had land intercommunication. If you do not think this necessary, might not New Zealand, etc., have been stocked during commencing Glacial period by occasional means from antarctic land? As for lowlands of Borneo being tenanted by a moderate number of temperate forms during the Glacial period, so far [is it] from appearing a "frightful assumption" that I am arrived at that pitch of bigotry that I look at it as proved!

LETTER 375. J.D. HOOKER TO CHARLES DARWIN. Kew, December 25th, 1866.

I was about to write to-day, when your jolly letter came this morning, to tell you that after carefully going over the N.Z. Flora, I find that there are only about thirty reputed indigenous Dicot. annuals, of which almost half, not being found by Banks and Solander, are probably non-indigenous. This is just 1/20th of the Dicots., or, excluding the doubtful, about 1/40th, whereas the British proportion of annuals is 1/4.6 amongst Dicots.!!! Of the naturalised New Zealand plants one-half are annual! I suppose there can be no doubt but that a deciduous-leaved vegetation affords more conditions for vegetable life than an evergreen one, and that it is hence that we find countries characterised by uniform climates to be poor in species, and those to be evergreens. I can now work this point out for New Zealand and Britain. Japan may be an exception: it is an extraordinary evergreen country, and has many species apparently, but it has so much novelty that it may not be so rich in species really as it hence looks, and I do believe it is very poor. It has very few annuals. Then, again, I think that the number of plants with irregular flowers, and especially such as require insect agency, diminishes much with evergreenity. Hence in all humid temperate regions we have, as a rule, few species, many evergreens, few annuals, few Leguminosae and orchids, few lepidoptera and other flying insects, many Coniferae, Amentaceae, Gramineae, Cyperaceae, and other wind-fertilised trees and plants, etc. Orchids and Leguminosae are scarce in islets, because the necessary fertilising insects have not migrated with the plants. Perhaps you have published this.

LETTER 376. TO J.D. HOOKER. Down, January 9th [1867].

I like the first part of your paper in the "Gard. Chronicle" (376/1. The lecture on Insular Floras ("Gard. Chron." January 1867).) to an extraordinary degree: you never, in my opinion, wrote anything better. You ask for all, even minute criticisms. In the first column you speak of no alpine plants and no replacement by zones, which will strike every one with astonishment who has read Humboldt and Webb on Zones on Teneriffe. Do you not mean boreal or arctic plants? (376/2. The passage which seems to be referred to does mention the absence of BOREAL plants.) In the third column you speak as if savages (376/3. "Such plants on oceanic islands are, like the savages which in some islands have been so long the sole witnesses of their existence, the last representatives of their several races.") had generally viewed the endemic plants of the Atlantic islands. Now, as you well know, the Canaries alone of all the archipelagoes were inhabited. In the third column have you really materials to speak of confirming the proportion of winged and wingless insects on islands?

Your comparison of plants of Madeira with islets of Great Britain is admirable. (376/4. "What should we say, for instance, if a plant so totally unlike anything British as the Monizia edulis...were found on one rocky islet of the Scillies, or another umbelliferous plant, Melanoselinum...on one mountain in Wales; or if the Isle of Wight and Scilly Islands had varieties, species, and genera too, differing from anything in Britain, and found nowhere else in the world!")

I must allude to one of your last notes with very curious case of proportion of annuals in New Zealand. (376/5. On this subject see Hildebrand's interesting paper "Die Lebensdauer der Pflanzen" (Engler's "Botanische Jahrbucher," Volume II., 1882, page 51). He shows that annuals are rare in very dry desert-lands, in northern and alpine regions. The following table gives the percentages of annuals, etc., in various situations in Freiburg (Baden):—

Annuals. Biennials. Perennials. Trees and Shrubs. Sandy, dry, and stony places: 21 11 65 3

Dry fields: 6 4 90

Damp fields: 12 2 77 9

Woods and copses: 3 2 65 31

Water: 3 97

Cultivated land: 89 11

Are annuals adapted for short seasons, as in arctic regions, or tropical countries with dry season, or for periodically disturbed and cultivated ground? You speak of evergreen vegetation as leading to few or confined conditions; but is not evergreen vegetation connected with humid and equable climate? Does not a very humid climate almost imply (Tyndall) an equable one?

I have never printed a word that I can remember about orchids and papilionaceous plants being few in islands on account of rarity of insects; and I remember you screamed at me when I suggested this a propos of Papilionaceae in New Zealand, and of the statement about clover not seeding there till the hive-bee was introduced, as I stated in my paper in "Gard. Chronicle." (376/6. "In an old number of the "Gardeners' Chronicle" an extract is given from a New Zealand newspaper in which much surprise is expressed that the introduced clover never seeded freely until the hive-bee was introduced." "On the Agency of Bees in the Fertilisation of Papilionaceous Flowers..." ("Gard. Chron." 1858, page 828). See Letter 362, note.) I have been these last few days vexed and annoyed to a foolish degree by hearing that my MS. on Domestic Animals, etc., will make two volumes, both bigger than the "Origin." The volumes will have to be full-sized octavo, so I have written to Murray to suggest details to be printed in small type. But I feel that the size is quite ludicrous in relation to the subject. I am ready to swear at myself and at every fool who writes a book.

LETTER 377. TO J.D. HOOKER. Down, January 15th [1867].

Thanks for your jolly letter. I have read your second article (377/1. The lecture on Insular Floras was published in instalments in the "Gardeners' Chronicle," January 5th, 12th, 19th, 26th, 1867.), and like it even more than the first, and more than this I cannot say. By mere chance I stumbled yesterday on a passage in Humboldt that a violet grows on the Peak of Teneriffe in common with the Pyrenees. If Humboldt is right that the Canary Is. which lie nearest to the continent have a much stronger African character than the others, ought you not just to allude to this? I do not know whether you admit, and if so allude to, the view which seems to me probable, that most of the genera confined to the Atlantic islands (I do not say the species) originally existed in, and were derived from, Europe, [and have] become extinct on this continent. I should thus account for the community of peculiar genera in the several Atlantic islands. About the Salvages is capital. (377/2. The Salvages are rocky islets about midway between Madeira and the Canaries; and they have an Atlantic flora, instead of, as might have been expected, one composed of African immigrants. ("Insular Floras," page 5 of separate copy.)) I am glad you speak of LINKING, though this sounds a little too close, instead of being continuous. All about St. Helena is grand. You have no faith, but if I knew any one who lived in St. Helena I would supplicate him to send me home a cask or two of earth from a few inches beneath the surface from the upper part of the island, and from any dried-up pond, and thus, as sure as I'm a wriggler, I should receive a multitude of lost plants.

I did suggest to you to work out proportion of plants with irregular flowers on islands; I did this after giving a very short discussion on irregular flowers in my Lythrum paper. (377/3. "Linn. Soc. Journ." VIII., 1865, page 169.) But what on earth has a mere suggestion like this to do with meum and tuum? You have comforted me much about the bigness of my book, which yet turns me sick when I think of it.

THE END