My dear Darwin

On the arrival of your last welcome letter I did determine to answer it that same day, but I went to a nice musical party in the evening & on my return remembered one of my next days lectures, which proved such a soporific that my answer to you was postponed sine die.

Here are two or three more notices on passages of the Journal, really from the progress I make (it is any thing but flattering) one would suppose that I found it the dullest book in life. As it is these must be too late, for which I can readily console myself in the full conviction of their futility.

May we not be at cross purposes anent the Fog on the Corcovado. I have no idea of denying the cause of its ascent, but still am obstinate enough to attribute its presence to the coolness & not heat of the leaves of the trees. My notion is, that leaves when living could not be heated to the xtent your statement leads one to suppose these ought to have been.¹ I should have expected the moisture to hang about the branches, exactly as on the grass in the morning: now after a thunder-plump we never see the vapor steaming up from a grass plot, & still less should it from the far more broken surface of a wood. However you know far more of the matter than I do, but one cannot help having his notions.

Do tell me where to expand a little that about the plants driven up the mountains from the change of temperature: I think I understand you, but not sufficiently to explain myself, will not Antarctic Botany illustrate the subject any way?

I called Watson a renegade for starting with the motto “omne ex ovo” which I took in its vulgar sense of “species are constant” & finishing almost an avowed believer in Progressive developement,² as enunciated & upheld in the already defunct “Vestiges”.

My Students like Physiological Botany far better than any other branch, & it is no joke coaching up lectures on these subjects, though a very useful employment. Do not suppose I am overworking myself, I am not, & as the garden is almost a mile from my home I get a good walk twice a day. I do not know D^r Coldstream, if I meet him I shall not forget your message.

The more I ponder upon Insular Floras the less inclined I am to admit the mutation of species to any very great amount, it is no doubt an ever active agent, but I should look upon it & upon Hybridizing &c as the perturbing causes of our difficulties in assigning limits to species, that have in many cases rendered it hopeless to search for specific characters. The species of Insular Floras are I think peculiarly well defined & I can hardly conceive a peculiar genus to have 5 peculiar species in an isolated spot only a few miles in circumference, if these are the offspring either of progressive developement or of variation. The absence of Insects limits the operation of hybridizing in these cases. Are not Hymenoptera particularly rare in these oceanic specks—?

Would you connect the absence or rather the destruction of Kerg. Land. wood i.e. vegetation with any supposed alteration of the temperature of the Antarctic ocean.³ Fuegia is rising, but I should think the mean temp. of those Lats. would rise with the increase of land to the N^d. of 60, & the contrary with land to the Southwd of 60, as the present configuration of that ugly corner of the world remains.

I am sorry to hear that you have been still suffering a little. I would willingly take a little bad health (temporarily only) to let you work a bit in comfort, you do so richly deserve a little peaceful working. I am finishing this, or rather writing almost all in poor Grahams⁴ sick room. he is very ill, in constant agony of pain, the mind is still clear, but all the bodily vigor gone & himself reduced to the lowest stage of emaciation, too weak to converse & sometimes to speak even, for hours together.

Lest I forget, what particular information is it you want about the plains of India,? is it about boulders,? I write there every month & my friend is a tolerably good observer.⁵ What a curious mixture of the Cape & Fuegian flora Tristan d’Acunha presents. Certes Kerg. Land is allied to Fuegia in the Flora though it has some very peculiar species of its own, as the Cabbage & one or two other things, still out of 18 genera I think all but the two are S. American. Thus Ranunculus¹ 1 sp. probably identical, Acæna², sp new?— Montia³ Callitriche⁴ Limosella⁵ 1 species of each & all Fuegian;— Juncus⁶ do.— Aira?⁷ do,— Agrostis⁸ do,— Festuca⁹ do,— Poa¹⁰ one sp peculiar & another¹¹ species peculiar?— Galium¹² sp.?.— Azorella¹³ sp?— Leptine¹⁴ lla a Fuegian genus, the species & Auckld Isld.— Bulliarda¹⁵ Fuegian;— Cabbage¹⁶ & another¹⁷ new genus peculiar to Kerg. Land.— Colobanthus¹⁸ Fuegian genus.. I think that 10 at least, probably 12, are thus or will prove Fuegian species; 6 are Auckland’s group species, all but one of these latter common to all antarctic countries.

As to the Polyborus I am no ornithologist, but do hope to shew you the two birds I mean, & if not distinct I will eat them,—bad as “Johny Rooks” are. I think I have three Hawks proper & 2 Polybori from the Falklands, both Polybori I think are Fuegian species. The piece of Amber I referred to is perfectly beautiful, enclosing innumerable ants, as beautiful as when alive, many of them had been carrying their eggs about when enclosed. Your Abrolhos plants I remarked along with the general Tropical collection, they looked uninviting, but must be done something with: the Islands are, as far as plants are concerned, too recently populated to be very interesting as a Botanical station, but highly interesting as illustration of what plants are easiest transported & what agents are most active in transportation.

Do intreat collectors in your instructions⁶ to distinguish between native & introduced plants, there is scarcely a pure flora known to me except Kerguelens lands. Even Lord Aucklands group had Poa annua & a chickweed on the tomb of a French sailor.

Journal 192.⁷ Luminous patches exactly as you described I fished up often with the net loaded by a deep-sea-lead & found there very large Pyrosoma.

200 Warm-blood sucking Insects: the Midge is another instance & some horrors at New Zealand.

235. in note— Was not the V. D. L. savage lower than the Fuegian,? he had hardly the canoe. Have we any instance of any extra Europæan & Asiatic nations improving their implements? domestic or otherwise? Good as the Chinese are, they do not improve their junks. Have we signs of progressions improvements even in the most useful implements in any savage nation? I should like a good essay on this subject, do you know any?—

257 Ant. geese, is the not the differently colored legs of the sexes an anomaly in Birds.

304. The Fucus giganteus or Macrocystis pyrifera goes N. to Rio San Francisco in California, there is but one species I think, or if 2 one is very rare indeed. I think it is also a Kamschatka plant.⁸ It is curious that it, the Albatross