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Darwin Correspondence Project

To E. R. Lankester   15 April [1873]1

Down

April 15th.

My dear Sir

Very many thanks for your kind consideration. The correspondence was in the Athenæum.2 I got some mathematician to make the calculation and he blundered and caused me much shame.— I send scrap of proof from last edition of Origin, with the calculation corrected. What grand work you did at Naples.3 I can clearly see that you will some day become our first star in Natural History

Yours very sincerely | Ch. Darwin

[Enclosure]4

Extract. “naturally increases at so high a rate, that, if not destroyed, the earth would soon be covered by the progeny of a single pair. Even slow-breeding man has doubled in twenty-five years, and at this rate, inless than a thousand years, there would literally not be standing-room for his progeny. Linnæus has calculated that if an annual plant produced only two seeds—and there is no plant so unproductive as this—and their seedlings next year produced two, and so on, then in twenty years there would be a million plants. The elephant is reckoned the slowest breeder of all known animals, and I have taken some pains to estimate its probable minimum rate of natural increase; it will be safest to assume that it begins breeding when thirty years old, and goes on breeding till ninety years old, bringing forth six young in the interval, and surviving till one hundred years old; if this be so, after a period of from 740 to 750 years there would be nearly nineteen million elephants alive, descended from the first pair.”

Footnotes

The year is established by CD’s reference to Lankester’s work at Naples, the results of which were published in February 1873 (see n. 3, below).
No letter from Lankester to CD before this date has been found. CD refers to letters that appeared in the Athenæum in 1869 (see Correspondence vol. 17, letter from Ponderer to the Athenæum, [before 5 June 1869], and letter to the Athenæum, 19 June 1869). The letters discussed a passage in Origin 4th ed., p. 74 (see n. 4, below).
Lankester worked in Naples from 13 October 1871, studying the early stages of development in various marine invertebrates. In April 1872, he became seriously ill with typhoid and was well enough to return to England only in May (Lester 1995, pp. 43–8). A summary of the results of his research appeared in Annals and Magazine of Natural History, February 1873, pp. 81–98 (Lankester 1873a).
The extract is from Origin 6th ed., p. 51. In Origin 4th ed., p. 74, the end of the sentence reads, ‘if this be so, at the end of the fifth century there would be alive fifteen million elephants, descended from the first pair.’

Summary

Discusses error in CD’s calculation of natural increase of elephants.

Includes extract from Origin.

Letter details

Letter no.
DCP-LETT-8287
From
Charles Robert Darwin
To
Edwin Ray Lankester
Sent from
Down
Source of text
DAR 146: 31
Physical description
2pp

Please cite as

Darwin Correspondence Project, “Letter no. 8287,” accessed on 22 January 2018, http://www.darwinproject.ac.uk/DCP-LETT-8287

Also published in The Correspondence of Charles Darwin, vol. 21

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