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
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.”
Please cite as “DCP-LETT-8287,” in Ɛpsilon: The Charles Darwin Collection accessed on