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Darwin Correspondence Project

To John Scott   15 January 1872

Down, Beckenham, Kent,

Jan. 15, 1872.

My Dear Sir,—

Many years ago I wrote a paper showing that stones laid on a grass field gradually become completely covered up by worm castings. I am now resuming the subject and making more accurate observations, as I believe they will bear on the denudation of the land.1 You will remember the appearance of lawns, fields, and commons in England, especially during the autumn. Now I want much to know whether in India worms eject their castings on the surface in like manner.2 A surface which is continually dug is not good for observation, but I suppose you could find some neglected part of the garden which you could observe. I find here abundant castings even in rather thick woods. If there are such castings, I should like to know whether they are numerous, and whether they are larger or smaller than those in England. If you could spare the time I should be very glad to hear how any two or three fresh castings marked by you disappeared. Does the heavy tropical rain wash them quickly away? The heavy rain in England causes a fresh casting to subside into a disk which will flow an inch or so down a slope. If they once get dry they endure for a surprising time, crumble into pellets, with part washed away and the remainder covered by growing grass. If these trifling observations would not trouble you, I should be really obliged. If you watch any fresh castings, you would have to enclose with stakes or somehow the spot, so that no one might trample them down.

My Dear Sir, yours very sincerely, | Ch. Darwin.

I wrote to you a month or two ago.3

N.B.—I have not yet been able to ascertain whether the castings on a sandy soil ever disintegrate into dust or powder, so that they can be blown away.

Have you ever observed how deep worms burrow in India?


CD refers to ‘Formation of mould’, which was read before the Geological Society of London in 1837. See also letter to Asa Gray, 15 January 1872.
CD used information from Scott in Earthworms, pp. 123–8.


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

Earthworms: The formation of vegetable mould through the action of worms: with observations on their habits. By Charles Darwin. London: John Murray. 1881.

‘Formation of mould’: On the formation of mould. [Read 1 November 1837.] Transactions of the Geological Society of London 2d ser. 5 (1840): 505–9. [Shorter publications, pp. 124–7.]


Is resuming the study of worm-casts as he believes they will bear on the denudation of land. Requests specific information on the relative number, size, and manner of deterioration of worm-casts in India.

Letter details

Letter no.
Charles Robert Darwin
John Scott
Sent from
Source of text
Transactions of the Hawick Archæological Society (1908): 68

Please cite as

Darwin Correspondence Project, “Letter no. 8159F,” accessed on 10 April 2021,

Also published in The Correspondence of Charles Darwin, vol. 20