Ɛpsilon

From Francis Darwin   [25–7 May 1880]1

My dear Father,

I hope you got a telegram about Convulvulus.2 The thing I found on working out the measurements is that they told nothing at all. A day is too long a period—the bits of stem which are growing well grow at a tremendous rate for a couple of days & then almost stop so that I could never get any fair comparisons3

Today I am measuring 4 plants every 4 hrs 7 am—11—3—7 pm   I can measure to 12 mm & I think with the rapid growth of 1 to 212 mm pr hour I ought to make out. They have alternate 4 hr periods of light & dark— If I see no good results today I shall shut up.

Please give my love to Sara & say I hope it will not matter my coming later instead of when I ought to   I think I must go to Brittany by a boat leaving S’hampton Monday night4   I wonder if Ubbadub remembers S’hampton at all.5 | Yrs affec F. D.

I shall certainly come on Friday6

1
The date is established by the references to CD’s and Francis Darwin’s visits to Southampton; Francis must have written after Emma and CD’s departure for Southampton on 25 May and before his arrival there on 28 May (see nn. 4 and 6, below).
2
The telegram has not been found. Convolvulus is the genus of bindweed. On 4 May 1880, CD recorded that he was working on sleep in cotyledons of C. major (a synonym of Ipomoea purpurea, common morning-glory; DAR 209.9: 12). Another undated note, about the growth of C. major in sand, records a task for Francis: ‘Get Frank to give prescription about the nutritive fluids—’ (DAR 68: 21).
3
Francis Darwin appears to have been trying to measure the rate of growth of plants relative to the amount of light present; he was possibly using the auxanometer (a self-recording instrument for measuring growth) built by Horace Darwin in 1876 (F. Darwin and Acton 1894, p. 140 n. 2).
4
CD stayed with Sara and William Erasmus Darwin in Southampton from 25 May to 8 June 1880 (CD’s ‘Journal’ (Appendix II)). Emma Darwin’s diary records that Francis Darwin left for Brittany on Monday 31 May 1880 (DAR 242).
5
Ubbadub was a pet name for Francis’s 3-year-old son, Bernard Darwin; Bernard and Francis lived with CD and Emma Darwin, and had accompanied them to Southampton on their previous annual visit (letter from Emma Darwin to H. E. Litchfield, [10 May 1879] (DAR 219.9: 196)).
6
Emma Darwin’s diary records that Francis Darwin arrived in Southampton on Friday 28 May 1880 (DAR 242).

Please cite as “DCP-LETT-12616F,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-12616F