Ɛpsilon

From Leonard Darwin   [29 March 1872]1

Dear Father

The following is the solid content of the box, which I forgot to measure last week.

211.44 Cubic inches

Your affec son. | Leonard Darwin

Iron box of earth.

Measurement after being well dried before the fire. = 180.8 Cubic inches. This shews that it has diminished 10 per cent on the original earth, without taking into account internal shrinking, although cracks were visible on the surface.2

CD note:

March. 29.1872.

Leonard

Earth dug out of ground & thrown up in fortification   increase ⁠⟨⁠of⁠⟩⁠ above 112th of bulk.—3

1
The date is established by CD’s note.
2
In Earthworms, pp. 161–2, where he gave measurements of dried earth by weight rather than volume, CD concluded that the largest castings were produced on the poorest soils, indicating that worms had to swallow a greater amount of earth on poor land in order to obtain enough food.
3
A further set of calculations, made by George Howard Darwin on the letter, estimates that the loss in volume of the dried earth is approximately 116.

Please cite as “DCP-LETT-8260,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-8260