skip to content

Darwin Correspondence Project

From Henry Johnson   12 January [1872?] 1


Jan 12

Dear Darwin,

You need not make any apology for troubling me, as you call it, by helping you in your investigation of the subject of mould. I have great pleasure in doing it.2

My Son Arthur has endeavoured to shade the map so as to represent the slope of the ground from the field B. towards the “Old wall” &. the Blacksmiths shop; and it should have been down to the River.3

I cannot tell how many feet the upper part of the field is higher than the lower, but I think I could form a guess by going over again.

It is very singular, as you say, that in all the 3 pits at the top of the field B—an obstruction was found at 9 or 10 inches, whilst at the bottom of the same field the mould was deeper. The best way to decide the matter will be for us to dig a few more holes at the very top of the field B, & see if the mould always rests upon stony obstruction, or if we find it exceed 9 inches when there


The year is conjectured from the possible relationship between this letter and the letter to Henry Johnson, 23 December 1871 (Correspondence vol. 19).
CD had asked Johnson to observe the thickness of mould covering the Roman remains at Wroxeter, Shropshire (see Correspondence vol. 19, letter to Henry Johnson, 23 December 1871, and Earthworms, pp. 221–8).
Arthur Peters Johnson. The map has not been found.


Sends a map of a field showing the effect of earthworms.

Letter details

Letter no.
Henry Johnson
Charles Robert Darwin
Sent from
Source of text
DAR 168: 65
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 12419,” accessed on 10 June 2023,