To Francis Darwin   [30 April 1876]1

[6 Queen Anne Street, London.]

Sunday—

My dear Frank—

I have just had a long & most valuable interview w. Frankland.2 He almost laughs at the idea of your getting potash & soda out of the soil by treating it w. Sulph. Acid & washing. On the other hand he thinks the evidence of plants not growing on the heap of red Clayey sand is probably very good that it does not contain these alkalis or phosphorus, I feel sure that we had better not plant the seeds as yet. He has undertaken to have both the washed & natural clayey sand carefully analysed.3

No time had better be lost.

He says from half to 1lb of each kind wd be sufficient; but you had better send full 1 lb. I shd. think they had better be put into washed tin canisters, of which I think you will find some in my study.

Lettington4 will remember where the pile in the sand walk was got from. You can then go with a clean trowel scrape off the outer surface & get about 1lb of it. There wd be no occasion to ask permission of Jessop.5 Each parcel must be labelled as by enclosed slip. Frankland asked for a mem.d— what substances are to be searched for

I also enclose address for the box in which the 2 parcels are to be packed & have the carriage paid

Yours affectly— | C. Darwin

I have had also a most interesting talk on chemical affinity, & he showed me a bull-finch getting out the ovules of Primrose-flowers beautifully.—6

[Enclosure]

Packets to be labelled

“From Mr. Darwin earth burnt, treated with sulphuric acid & washed

“From Mr Darwin Natural earth from a considerable depth, supposed to be almost destitute of what will support plants

A Memorandum to be added, addressed to Prof. Frankland & enclosed with the 2 parcels

“Mr Darwin wishes to know whether these parcels of earth contain any Potassium, Sodium, Lime, Magnesia, Phosphorus or Sulphur.—

(I cannot remember any other substance)

Dr. Frankland

Royal College of Chemistry

South Kensington Museum

LS(A)

Postmark: 1 MY 76

1
The date is established from the postmark. The Sunday before 1 May 1876 was 30 April 1876.
2
CD visited Frankland on 30 April 1876; see letter to Edward Frankland, 27 April [1876] and n. 3.
3
CD was trying to make soil free from nutrients for his experiments on crossing and self-fertilisation. He had sought advice from Joseph Henry Gilbert at the Rothamsted Agricultural Station; see letter to J. H. Gilbert, 16 February 1876, and letter from J. H. Gilbert, 4 March 1876.
4
Henry Lettington was a gardener at Down House.
5
Edward Jessup farmed the land adjacent to Down House from where the soil CD wanted evidently came.
6
See letter to Edward Frankland, 27 April [1876] and n. 3. Margaret Frankland’s diary entry for the 30 April 1876 (see Russell 1996, pp. 331–2) recorded a demonstration of an experiment with primroses and bullfinches; Edward Frankland had written to CD about it in 1874 (see Correspondence vol. 22, letter from Edward Frankland, 30 April 1874, and letter to Nature, 7 and 11 May [1874]): In the mng at 10 o’clock Mr. Darwin arrived & was received by the whole family assembled in the drawing room (which was pre-arranged.) The birds were also in the room & some primroses & cowslips so Papa repeated the experiment before Mr. Darwin. For almost the first time the bullfinch eat the corolla instead of the ovary of these flowers; but it soon showed its decided predilection for the latter. The canary on the other hand pecked the flowers indiscriminately.

Manuscript Alterations and Comments

1.6 both] interl in CD’s hand
3.1 but you … 1 lb. 3.2] interl in CD’s hand
6.1 C … beautifully— 7.2] in CD’s hand
Enclosure:
1.1 Packets … substance 6.1] in CD’s hand
3.1 supposed … plants 3.2] del but dots beneath and marked ‘stet’
3.2 will] above del ‘will’
5.1 any] interl
6.1 (I … substance)] parentheses added pencil
6.1 remember any] ‘any’ after del ‘anyth’

Please cite as “DCP-LETT-10485B,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-10485B