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Showing 21–40 of 1371 items
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Asks if J. E. Gray has returned [printing] estimates for Zoology.
Henslow has some Galapagos plants which he forgot to forward to JDH.
Encloses letter from Ehrenberg [758] about Infusoria.
Intends to visit Kew.
Health and weather permitting, CD proposes to visit Kew.
Encloses letter from Ehrenberg [762], who wants information on deep-sea soundings from JDH’s voyage, and on isolated islands.
Encloses Ehrenberg letter, Galapagos seaweed, and specimens of Conferva.
H. Denny would like specimens of Antarctic Pediculi.
No summary available.
Encloses pamphlet from Ehrenberg who asks about deep-sea soundings from JDH’s voyage.
Suggests there is a direct relation between temperature and abundance of plant species.
Acknowledges note and parcel for Ehrenberg.
Considers why different areas have different numbers of species. Gives an example opposing JDH’s view that paucity of species results from vicissitudes of climate. CD has concluded that species are most numerous in areas that have most often been divided, isolated from, and then reunited with, other areas. Cannot give detailed reasons but believes that "isolation is the chief concomitant or cause of the appearance of new forms".
Discusses the connection between climate and vegetation. Believes that an equable climate is unfavourable to increase of species either by importation or modification of existing forms; illustrates his view with reference to particular floras. Hopes to acquire facts to support CD’s idea that isolation is important in producing new forms. Considers the floras of islands some of which do have distinctive species but others of which do not. Agrees that the wide ranges of cryptogams are a consequence of their means of dispersal. Asks for references to works on original creation and species mutability in order to get the best notions of "the (mad) theories of some men from Lamarck’s twaddle upwards".
Sends notes on Infusoria for Ehrenberg.
Comments on distribution of species in natural orders that have local distributions. Intermediate forms between species of Lycopodium.
Origin of Antarctic brash ice.
Further on case of Lycopodium: does JDH know any genera of plants whose species are variable in one continent but not in another? Discussion on variations between floras as regards species richness, and factors affecting geographical distribution. On species, CD expects "that I shall be able to show even to sound naturalists that there are two sides to the question of the immutability of species; – that facts can be viewed and grouped under the notion of allied species having descended from common stocks". Mentions books and papers for and against species mutability. CD believes past absurd ideas arose from no one’s having approached subject on side of variation under domestication.
Would like to see Clarke’s paper
and would welcome visit from JDH.
Differences in variability of species within a single genus. Further observations on Lycopodium.
Interested in Humboldt’s river with different floras on opposite banks, and other unexplained cases of very local distributions.
Would like JDH to visit. Regrets he will not be fit to visit JDH.
Would like to visit on the weekend of 7–8 December.
Differences in floras of St Helena and Ascension.
Instructions for JDH’s trip to Down.
Change in train times.