Ɛpsilon

To W. H. Miller   27 December [1860]1

Down Bromley Kent.

Dec 27

My dear Miller,

I hope this will come in time to save you any more trouble.2 I have just measured some walls in the same manner as I did before and I find the same thickness in both basal plates and hexagonal prism, viz about 52000 which is rather thicker than you made them. I can only account for my strange blunder by my having two micrometers, one ruled with lines exactly twice as far apart. I will take average of your six measurements and give that as about the thickness of walls.3 With cordial thanks for all your kindness, and grief at causing you so much trouble by my scandalous blunder which I will correct.

Believe me yours very sincerely | C Darwin

P.S. | Unless you happen to have made more measurements, I will give the thickness not on your authority; but if you do give me accurate thickness I will then say that you measured thickness for me.

Copy

1
The year is given by the reference to the preparation of the third edition of Origin (see n. 3, below).
2
CD probably refers to work carried out by Miller in response to the letter to W. H. Miller, 1 December [1860]. No letter from Miller detailing his results has been found.
3
The ‘blunder’ to which CD alludes is his statement in the first edition of Origin, p. 231, that the walls of bees’ cells were ‘about one four-hundredth of an inch in thickness; the plates of the pyramidal basis being about twice as thick.’ The third edition was corrected to read (Origin 3d ed., p. 252): These walls, as Professor Miller has kindly ascertained for me, vary greatly in thickness; being, on an average of twelve measurements made near the border of the comb, 1\/353 of an inch in thickness; whereas the basal rhomboidal plates are thicker nearly in the proportion of three to two, having a mean thickness, from twenty-one measurements, of 1\/229 of an inch.

Please cite as “DCP-LETT-2609,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-2609