|
MORE LETTERS OF CHARLES DARWIN VOLUME II
MORE LETTERS OF CHARLES DARWIN VOLUME II CHARLES DARWIN MORE LETTERS OF CHARLES DARWIN
VOLUME II
CHAPTER 2.VII.--GEOGRAPHICAL DISTRIBUTION.
1843-1882 (Continued) (1867-1882.)
LETTER 378. J.D. HOOKER TO CHARLES DARWIN.
Kew January 20th 1867.
Prof. Miquel of Utrecht begs me to ask you for your carte and offers his
in return. I grieve to bother you on such a subject. I am sick and tired
of this carte correspondence. I cannot conceive what Humboldt's Pyrenean
violet is: no such is mentioned in Webb and no alpine one at all. I am
sorry I forgot to mention the stronger African affinity of the eastern
Canary Islands. Thank you for mentioning it. I cannot admit without
further analysis that most of the peculiar Atlantic Islands genera were
derived from Europe and have since become extinct there. I have rather
thought that many are only altered forms of existing European genera; but
this is a very difficult point and would require a careful study of such
genera and allies with this object in view. The subject has often
presented itself to me as a grand one for analytic botany. No doubt its
establishment would account for the community of the peculiar genera on the
several groups and islets but whilst so many species are common we must
allow for a good deal of migration of peculiar genera too.
By Jove! I will write out next mail to the Governor of St. Helena for boxes
of earth and you shall have them to grow. Thanks for telling me of having
suggested to me the working out of proportions of plants with irregular
flowers in islands. I thought it was a deuced deal too good an idea to
have arisen spontaneously in my block though I did not recollect your
having done so. No doubt your suggestion was crystallised in some corner
of my sensorium. I should like to work out the point.
Have you Kerguelen Land amongst your volcanic islands? I have a curious
book of a sealer who was wrecked on the island and who mentions a volcanic
mountain and hot springs at the S.W. end; it is called the "Wreck of the
Favourite." (378/1. "Narrative of the Wreck of the 'Favourite' on the
Island of Desolation; detailing the Adventures Sufferings and Privations
of John Munn; an Historical Account of the Island and its Whale and Sea
Fisheries." Edited by W.B. Clarke: London 1850.)
LETTER 379. TO J.D. HOOKER.
Down March 17th 1867.
It is a long time since I have written but I cannot boast that I have
refrained from charity towards you but from having lots of work...You ask
what I have been doing. Nothing but blackening proofs with corrections. I
do not believe any man in England naturally writes so vile a style as I
do...
In your paper on "Insular Floras" (page 9) there is what I must think an
error which I before pointed out to you: viz. you say that the plants
which are wholly distinct from those of nearest continent are often very
common instead of very rare. (379/1. "Insular Floras" pamphlet reprinted
from the "Gardeners' Chronicle" page 9: "As a general rule the species of
the mother continent are proportionally the most abundant and cover the
greatest surface of the islands. The peculiar species are rarer the
peculiar genera of continental affinity are rarer still; whilst the plants
having no affinity with those of the mother continent are often very
common." In a letter of March 20th 1867 Sir Joseph explains that in the
case of the Atlantic islands it is the "peculiar genera of EUROPEAN
AFFINITY that are so rare" while Clethra Dracaena and the Laurels which
have no European affinity are common.) Etty (379/2. Mr. Darwin's
daughter now Mrs. Litchfield.) who has read your paper with great
interest was confounded by this sentence. By the way I have stumbled on
two old notes: one that twenty-two species of European birds occasionally
arrive as chance wanderers to the Azores; and secondly that trunks of
American trees have been known to be washed on the shores of the Canary
Islands by the Gulf-stream which returns southward from the Azores. What
poor papers those of A. Murray are in "Gardeners' Chronicle." What
conclusions he draws from a single Carabus (379/3. "Dr. Hooker on Insular
Floras" ("Gardeners' Chronicle" 1867 pages 152 181). The reference to
the Carabidous beetle (Aplothorax) is at page 181.) and that a widely
ranging genus! He seems to me conceited; you and I are fair game
geologically but he refers to Lyell as if his opinion on a geological
point was worth no more than his own. I have just bought but not read a
sentence of Murray's big book (379/4. "Geographical Distribution of
Mammals" 1866.) second-hand for 30s. new so I do not envy the
publishers. It is clear to me that the man cannot reason. I have had a
very nice letter from Scott at Calcutta (379/5. See Letter 150.): he has
been making some good observations on the acclimatisation of seeds from
plants of same species grown in different countries and likewise on how
far European plants will stand the climate of Calcutta. He says he is
astonished how well some flourish and he maintains if the land were
unoccupied several could easily cross spreading by seed the Tropics from
north to south so he knows how to please me; but I have told him to be
cautious else he will have dragons down on him...
As the Azores are only about two-and-a-half times more distant from America
(in the same latitude) than from Europe on the occasional migration view
(especially as oceanic currents come directly from West Indies and Florida
and heavy gales of wind blow from the same direction) a large percentage
of the flora ought to be American; as it is we have only the Sanicula and
at present we have no explanation of this apparent anomaly or only a
feeble indication of an explanation in the birds of the Azores being all
European.
LETTER 380. TO J.D. HOOKER.
Down March 21st [1867].
Many thanks for your pleasant and very amusing letter. You have been
treated shamefully by Etty and me but now that I know the facts the
sentence seems to me quite clear. Nevertheless as we have both blundered
it would be well to modify the sentence something as follows: "whilst on
the other hand the plants which are related to those of distant
continents but have no affinity with those of the mother continent are
often very common." I forget whether you explain this circumstance but it
seems to me very mysterious (380/1. Sir Joseph Hooker wrote (March 23rd
1867): "I see you 'smell a rat' in the matter of insular plants that are
related to those of [a] distant continent being common. Yes my beloved
friend let me make a clean breast of it. I only found it out after the
lecture was in print!...I have been waiting ever since to 'think it out'
and write to you about it coherently. I thought it best to squeeze it in
anyhow or anywhere rather than leave so curious a fact unnoticed.")...Do
always remember that nothing in the world gives us so much pleasure as
seeing you here whenever you can come. I chuckle over what you say of And.
Murray but I must grapple with his book some day.
LETTER 381. TO C. LYELL.
Down October 31st [1867].
Mr. [J.P. Mansel] Weale sent to me from Natal a small packet of dry locust
dung under 1/2 oz. with the statement that it is believed that they
introduce new plants into a district. (381/1. See Volume I. Letter 221.)
This statement however must be very doubtful. From this packet seven
plants have germinated belonging to at least two kinds of grasses. There
is no error for I dissected some of the seeds out of the middle of the
pellets. It deserves notice that locusts are sometimes blown far out to
sea. I caught one 370 miles from Africa and I have heard of much greater
distances. You might like to hear the following case as it relates to a
migratory bird belonging to the most wandering of all orders--viz. the
woodcock. (381/2. "Origin" Edition VI. page 328.) The tarsus was
firmly coated with mud weighing when dry 9 grains and from this the
Juncus bufonius or toad rush germinated. By the way the locust case
verifies what I said in the "Origin" that many possible means of
distribution would be hereafter discovered. I quite agree about the
extreme difficulty of the distribution of land mollusca. You will have
seen in the last edition of "Origin" (381/3. "Origin" Edition IV. page
429. The reference is to MM. Marten's (381/4. For Marten's read Martins'
[the name is wrongly spelt in the "Origin of Species."]) experiments on
seeds "in a box in the actual sea.") that my observations on the effects of
sea-water have been confirmed. I still suspect that the legs of birds
which roost on the ground may be an efficient means; but I was interrupted
when going to make trials on this subject and have never resumed it.
We shall be in London in the middle of latter part of November when I
shall much enjoy seeing you. Emma sends her love and many thanks for Lady
Lyell's note.
LETTER 382. TO J.D. HOOKER.
Down Wednesday [1867].
I daresay there is a great deal of truth in your remarks on the glacial
affair but we are in a muddle and shall never agree. I am bigoted to the
last inch and will not yield. I cannot think how you can attach so much
weight to the physicists seeing how Hopkins Hennessey Haughton and
Thomson have enormously disagreed about the rate of cooling of the crust;
remembering Herschel's speculations about cold space (382/1. The reader
will find some account of Herschel's views in Lyell's "Principles" 1872
...
|
