From Francis Galton 4 June 1872
42 Rutland Gate SW
June 4/72
My dear Darwin
Thank you very much about the rabbits— I however sincerely trust you did not send your man all the way on purpose for them alone!1 Any how I feel I have put you to much trouble and can only repeat how greatly I am obliged.
Your criticisms on my paper are very gratifying to me the more so that the question you put, is one to which I can at once reply.2
You ask, why hybrids of the first generation are nearly uniform in character while great diversity appears in the grand children & succeeding generations?
I answer, that the diagram shews (see next page) that only 4 stages separate the children from the parents but 20 from their grand-parents and therefore judging from these limited data alone, (ignoring for the moment, all considerations of unequal variability in the different stages & of pre-potence of particular qualities, &c—) the increase of the mean deviation of the several grandchildren (from the average hybrid) over that of the several children is as /20:/4 or more than twice as great. The omitted considerations would make the deviation (as I am prepared to argue) still greater.3
I will add the explanatory foot-note you most justly suggest,4 & should be very glad if you wd. let me have your copy back (I will return it) with marks to the obscure passages that I may try to amend them.
I found the ⟨ ⟩ an uncommonly tough ⟨job⟩;—having to avoid hypothesis on the one hand & truism on the other and, again, the difficulty of being sufficiently general & yet not too vague.
It is very difficult to draw a correct verbal picture in mezzo tint, I mean by burnishing out the broad effects and not by drawing hard outlines.
Ever very sincerely | Francis Galton
I have knocked every symbol out of my paper & wholly rearranged the diagrams &c to make it less unintelligible.—5
FG
A pleasant journey & rest, to you all!6
Footnotes
Summary
Thanks CD for criticisms of his paper; explains why there is greater diversity among succeeding generations than in the first.
Letter details
- Letter no.
- DCP-LETT-8368
- From
- Francis Galton
- To
- Charles Robert Darwin
- Sent from
- London, Rutland Gate, 42
- Source of text
- DAR 105: A61–3
- Physical description
- ALS 5pp
Please cite as
Darwin Correspondence Project, “Letter no. 8368,” accessed on 24 April 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-8368.xml
Also published in The Correspondence of Charles Darwin, vol. 20