Ɛpsilon

To Josef Popper   15 February 1881

Down. | Beckenham, Kent. | (Railway Station | Orpington. S.E.R.)

Feb. 15. 1881

Dear Sir

I am sorry to say that it is impossible for me give you the least aid, as I have never attended to any mechanical subjects.—1 I shd. doubt whether it would be possible to train birds to fly in a certain direction in a body, though I am aware that they have been taught some tricks— Their mental powers are probably much below those of mammals.—

It is said, & I suppose truly, that an Eagle will carry a lamb, this shows that a bird may have great power for a short distance.—

I cannot remember your essay with sufficient distinctness to make any remarks on it.2 When a man is old & works hard, one subject drives others out of his head.—

I hope to read what you say about Mr. Bradlaugh.3

I remain | Dear Sir | Yours faithfully. | Ch. Darwin.

1
See the letter from Josef Popper, 11 February 1881, in which he asked CD whether it would be possible to train birds such as cranes or pelicans to fly in unison in order to develop a bird-powered flying machine.
2
Some years previously, Popper had sent CD an essay outlining a radical social theory (see letter from Josef Popper, 11 February 1881 and n. 3).
3
For Popper’s discussion of Charles Bradlaugh, see the letter from Josef Popper, 11 February 1881 and n. 5.

Manuscript Alterations and Comments

0.1 (Railway … S.E.R.)] parentheses added

Please cite as “DCP-LETT-13054,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-13054