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Darwin Correspondence Project

From Amy Ruck to Horace Darwin   [1 February 1872]1

Will you tell Mr. Darwin that in the case in which the furrows run down the hill & are 4in at the top & 1in at the bottom—the slope is 15o and faces North East. The furrows are about 7 ft apart & on the level ground above are 4in 312in deep, although it is difficult to measure these on account of the mole hills—40 paces long.

On another slope of 15o facing S. West the furrows were scarcely perceptible but on level ground at the bottom the same furrows were 314 212in deep. The length of the slope was 80 paces— On another short slope of 10o the furrows at the top were 312 at the bottom 114 112in deep.2

CD annotations

Top of letter: ‘Feb 1. 1872 (2d note)’
Bottom of letter: ‘Amy Ruck’


The date is established by CD’s annotation.
The measurements were made for CD’s research on the action of worms in turning over soil (see also letter from Amy Ruck to Horace Darwin, [20 January 1872]). CD wanted to ascertain how long the ridges of ploughed land would persist after the land was last ploughed (see Earthworms, p. 292).


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


Observations on earthworm activity in old furrows on a hillside.

Letter details

Letter no.
Amy Richenda (Amy) Ruck/Amy Richenda (Amy) Darwin
Horace Darwin
Sent from
Source of text
DAR 176: 222
Physical description
†(by CD)

Please cite as

Darwin Correspondence Project, “Letter no. 8193,” accessed on 25 January 2020,

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