Ɛpsilon

To Francis Darwin   6 January 1872

Down, | Beckenham, Kent.

Jan 6. 1872

My dear Frank

Very many thanks for all the trouble you have taken. I do not quite understand one or 2 points. You speak of ridges running down the slope; therefore I suppose your wavy line A is a horizontal section of the surface; but if so, how can yr Red letters D & E represent an upper & lower part of the same slope?1 Lastly, I do not feel sure whether the difference in thickness of the slope between top & bottom (where I have put 2 blue crosses) refers to the ridges & furrows, or to the upper & lower part of the slope.

Please to answer this at your leisure & return the enclosed & I am very much obliged for the trouble you have taken | yours affectly | Ch. Darwin

LS(A)

CD annotations

1.2 I suppose … surface; 1.3] ‘Yes’ added above, ink
1.3 but if so, … same slope? 1.4] ‘D & E are only to show that the 2 trenches were not cut across the same furrow’ added above, ink
1.5 difference … between] ‘No texture & color only’ added above, ink
1.6 upper & lower part of the slope. 1.7] ‘No to the top & bottom of trenches only’ added below, ink
1
Francis’s letter and diagram have not been found in the Darwin Archive–CUL. CD’s notes for Earthworms are in DAR 63–5. Francis wrote his answers to CD’s questions between the lines of the letter; see Francis Darwin’s annotations, at the end of the letter.

Manuscript Alterations and Comments

1.5 in thickness of the slope] interl in CD’s hand
2.1 & … enclosed] interl in CD’s hand

Please cite as “DCP-LETT-8147,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-8147