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Darwin Correspondence Project

From W. E. Darwin   [29 February 1872]1



My dear Father

Parsons has sent me the particulars of the chalk, roughly it comes to this, the pure lump chalk contains between 112 & 113 by weight of Clay &c & the powdered chalk taken from between the crevices of the lumps 110th.3 Does not this seem a great quantity to have been originally in the chalk. Is it likely that water with fine mould in solution would sink into the earth & penetrate the chalk? If I found that organic matter was contained in this residue from the chalk would that show anything? or would organic matter exist in the clay that was in the chalk at its formation; or in the chalk itself?

Do not trouble to answer this, as I shall be up in 10 days.

I send a mouth-piece which fits “Voronzoff” well, if it is inserted with a little screw & pinch.4

Your affect. son. | W.E.D.

I am surprised to see from the article in the Spect. that the fashionable swell Sir W. Gull takes the Descent of Man as a matter of course, as he argues from the supposition5

CD annotations

3.1 I … that the 5.1] crossed pencil
Top of letter: ‘Prestwich Address | 1871. Analysis of Chalk. | (Cigars)’ pencil; ‘Worms’ red crayon
End of letter: ‘.07 per cent of Alumina & iron | [‘.36del] | lowest ch’ pencil


The date is established by the reference to an article in the Spectator, 24 February 1872 (see n. 5, below). The Thursday following 24 February 1872 was 29 February.
Soton: Southampton.
Robert Mann Parsons was superintendent of the Ordnance Survey Office, Southampton. In Earthworms, p. 299, CD reported that Parsons determined that some powdered chalk collected near Winchester contained ten per cent earthy matter while fragmentary chalk from the same place contained eight per cent earthy matter. CD was trying to account for differences in depth of mould in different locations and concluded that the percolation of earthy matter into chalk accounted for some of them (see ibid., pp. 297–300).
‘Voronzoff’ was a Russian brand of cigarette. Early Russian cigarettes were notable for unusual mouthpieces (Evans [1921], p. 38).
An article in the Spectator, 24 February 1872, pp. 239–40, ‘Sir W. Gull on physiological intervention’, summarised William Withey Gull’s address to the Clinical Society, delivered on 26 January 1872. Gull had expressed his belief in the steady progress of nature and discussed the possibility of surgically removing vestigial organs in order to improve humans. No overt reference to CD or to Descent appeared in the article.


Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.

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

Evans, George. [1921.] The old snuff house of Fribourg & Treyer at the sign of the Rasp & crown: no. 34 St. James’s Haymarket, London, S.W., 1720, 1920. [London]: published for the author by D. Macbeth.


Amount of clay present in certain chalk samples.

Letter details

Letter no.
William Erasmus Darwin
Charles Robert Darwin
Sent from
Source of text
DAR 162: 102
Physical description
ALS 4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 7469,” accessed on 23 June 2024,

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