# From Leonard Darwin   7 May 1879

Brompton Barracks | Chatham

7—5—79

Dear Father

I am afraid that I have not been very successful in the weighing. In the first place the little bits had stuck rather firmly to the paper; it was difficult to get them off and in doing so a bit fell off the scale pan, but I am almost certain that I picked it all up. As to the weight I can only say that it was less than $\frac{1}{100}$ of a grain.1 The scale turned fairly well to the $\frac{1}{100}$ but hardly shewed any movement with the bits on it.

I enclose two sets of Dr. D’s letters, as a spare one might be useful.2 I have plenty more. Sorry not to have done better in the weighing.

Your affec son | Leonard Darwin

## Footnotes

The substance that Leonard was trying to weigh has not been identified, but in Movement in plants, p. 147, CD noted that specks of shellac removed from the tips of two radicles of broad beans (Vicia faba) together weighed less than one hundredth of a grain. This small coating of shellac on one side of the tip of the radicle had been sufficient to cause deflection. A grain is equal to approximately 64.8 milligrams.
Leonard probably photographed the letters from Erasmus Darwin that CD had found in Robert Waring Darwin’s deeds box (see letter to Reginald Darwin, 8 April 1879 and n. 2). In Erasmus Darwin, p. 16 n., CD noted that he had other letters photographed.

## Bibliography

Erasmus Darwin. By Ernst Krause. Translated from the German by W. S. Dallas, with a preliminary notice by Charles Darwin. London: John Murray. 1879.

Movement in plants: The power of movement in plants. By Charles Darwin. Assisted by Francis Darwin. London: John Murray. 1880.

## Summary

Has been trying unsuccessfully to weigh something for CD.

## Letter details

Letter no.
DCP-LETT-12035
From
Leonard Darwin
To
Charles Robert Darwin
Sent from
Brompton Barracks, Chatham
Source of text
DAR 186: 35
Physical description
3pp