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Letter 7319

Darwin, C. R. to Tyndall, John

8 Sept 1870


CD finds JT’s discourse “grand and most interesting” [On the scientific use of the imagination (1870)]. Flattered by what JT says about him.

He is “a rash man to say a good word for Pangenesis for it has hardly a friend among naturalists”.

CD is much struck with what JT says about “pondering” and delighted by his “as if” argument.


Down. | Beckenham | Kent. S.E.

Sep 8th. 1870

My dear Tyndall

Your whole discourse strikes me as grand & most interesting.f1 What yousay about Pangenesis is quite correct, & your expression, “not onlyis the organism as a whole wrapt up” &c is most happy.f2 What you sayabout me, coming as it does from you, has pleased me extremely, somuch that there must be clouds of vanity in my mind to bring out suchpleasant sensations as your remarks passed through them— you are arash man to say a word for Pangenesis, for it has hardly a friendamongst naturalists, yet after long pondering (how true your remarksare on pondering) I feel a deep conviction that Pangenesis will someday be generally accepted. I have been particularly delighted by your“as if” argument. These words have lately been fired at me, & if Ihad been forced to answer, I should not have known what to say, now Icd answer by a round of your artillery.f3 I have ventured to mark(p. 12. & 40) two sentences which seem to me not so perfectly lucid asall the rest. I may also mention that in the discussion on “theparticles of our sky” I read 2 or 3 pages thinking that you referredto the atoms of the air: wd it not be well for blunderersto shew in the early part, that you refer to foreign particles?f4

With hearty admiration & thanks, yours very truly | Ch. Darwin

P.S. I return the proofs by this post.

When in Brazil I was much struck with the frequent blue haze & Iquote (p. 32 of my travels) Humboldt’s remark on “the thin vapourwhich, without changing the transparency of the air, renders its tintsmore harmonious & softens its effects”.f5

It seemed to me that this phenomenon was much more strongly markedin the tropics than in our temperate regions—

On one day when the beautiful pale blue haze had come on very strong,the difference between the dew point & temperature by Daniel’shygrometerf6 had increased from 7o.5. to 17o

The Michael Faraday Museum at the Royal Institution ofGreat Britain, London, reference RI MS JT/2/10/458, spine title:Journal V111A 1858–71



CD refers to Tyndall 1870. See letter from John Tyndall, 7 September 1870.
CD’s hypothesis of pangenesis was presented in Variation 2: 357–404.Describing pangenesis, Tyndall had written: ‘Not only is theorganism as a whole wrapped up in the germ, but every organ of theorganism has there its special seed’ (Tyndall 1870, p. 32).
Tyndall used the expression ‘as if’ to describe the basis on whichcertain theoretical conceptions were believed. Thus the phenomena oflight occur as if the medium of the ether existed. He argued that manyassumptions of everyday life were based on the same ‘as if’ principle(Tyndall 1870, p. 10). For Tyndall’s discussion of pondering in relation to scientific discovery, see Tyndall 1867, p. 655, and Correspondence vol. 15, letter to J. D. Hooker, 2 September [1867] and n. 5.
The phrase ‘particles of our sky’ appears in Tyndall 1870, p. 26.
The quotation from Alexander von Humboldt appears on page 32 ofJournal of researches 2d ed.
CD refers to the dew-point hygrometer designed by John FredericDaniell (ODNB).
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