Ɛpsilon

To Samuel Newington   17 September 1875

Down, | Beckenham, Kent.

Sep 17. 75

My dear Sir

I am much obliged for your letter of Sep 2nd explaining to me about the vines. I should expect that the Madresfield vine was originally a sport of the Hamburgh & reverted to it after being in-arched.1 The case is very curious, but does not immediately concern me.

I have not received the specns. of berries which you intended to send me, but this is now of no importance. I have never heard of yr observations of roots secreting carbonic acid; but Prof: Sachs has proved this by growing plants in polished marbe pots.2 I return Sir J. Herschel’s letter; yr observation on the coincidence of the pulse & step are quite new to me.3

Dear Sir | Yrs faithfully | Ch. Darwin

LS

2
See letter from Julius von Sachs, 4 July 1875 and n. 8, and Sachs 1860 and 1864. Sachs had noted that air in the soil contained much more carbonic acid than air above ground, and that the source of the acid was the roots of plants (Sachs 1860, p. 118).

Please cite as “DCP-LETT-10159,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-10159