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Darwin Correspondence Project

To William Hallowes Miller   5 June [1860]1

Down Bromley Kent

June 5

My dear Miller

I thank you much for your letter.2 Had I seen the interest of my remark I would have made many more measurements though I did make several. I stated the facts merely to give the general reader idea of thickness of walls.3

Especially if I had seen that the fact had any general bearing I should have stated that as far as I could measure, the walls are by no means perfectly of the same thickness. Also I should have stated that the chief difference is when the thickness of walls of the upper part of the hexagon and of the pyramidal basal plates are contrasted    Will you oblige me by looking with a strong lens at the bit of comb, brushing off with a knife the upper thickened edges, and then compare, by eye alone, the thickness of walls there with the thickness of the basal plates, as seen in any cross section. I should very much like to hear whether, even in this way, the difference is not perceptible. It is generally thus perceptible by comparing the thickness of the walls of the hexagon (if not taken very close to the angle) near to the basal plates, where the comparison by eye is of course easier. Your letter actually turned me sick with panic, from not seeing any great importance of fact, till I looked at my notes, I did not remember that I made several measurements.4 I have now repeated some5 measurements roughly with same general results but difference I think is hardly double.6

I should not have mentioned the thickness of the basal plates at all, had I not thought it would give an unfair notion of the thickness of the walls, to state the lesser measurements alone—

With cordial and sincere thanks | Yours very truly | C. Darwin


Dated by the reference to CD’s discussion of bees’ cells in Origin.
Miller was professor of mineralogy at Cambridge University. In 1858 he had helped CD with his study of the geometry of bees’ cells (see Correspondence vol. 7, letters to J. D. Hooker, 10 April [1858], and to W. H. Miller, [15 April 1858], and letter from W. H. Miller, [14 May 1858]). Miller presumably wrote to CD after reading the discussion of the subject in Origin, pp. 224–35, in which CD cited Miller as his authority.
CD described his experiments to determine the mode of formation of the cell walls in Origin, pp. 228–31. He found that bees at first build thick walls and then gnaw them down to ‘an excessively thin finished wall’ (ibid., p. 231).
CD’s notes on bees’ cells are in DAR 48 (ser. 2): 5–77.
Francis Darwin was not certain whether this word was ‘some’ or ‘same’ and wrote a note to this effect on the copy of the letter.
CD refers to the sentence in Origin, p. 231, where he estimates that the plates of the pyramidal basis are about twice as thick as the hexagonal walls.


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

Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.


Discusses measurements of bees’ cells.

Letter details

Letter no.
Charles Robert Darwin
William Hallowes Miller
Sent from
Source of text
DAR 146
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 2468,” accessed on 26 January 2022,

Also published in The Correspondence of Charles Darwin, vol. 8