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Darwin Correspondence Project

From Trenham Reeks   15 November 1860

Museum, Jermyn St

15th. Novr. 1860.

My dear Mr. Darwin

It really gives me much pleasure to be able to render you any assistance in your interesting experiments and I hope you will never hesitate to let me know where or when I can be of use.1

On the other side you have the weights of the three objects.2 I first weighed them myself in our own balance, and then I asked my friend Mr. Tookey,3 who is known for his carefulness and accuracy, to do the same in his own assay-balance, which he considers to be about as accurate as can be made.

I may say that in both these balances “the beam is kicked” by the 11000 of a grain or .001 and practically I do not think Chemists attempt anything more delicate.

The difference in the weights I think may be explained by hydroscopic moisture as they were weighed on different days.


Believe me, Yours very sincerely | Trenham Reeks.


Reeks was curator and librarian of the Museum of Practical Geology, London. He had previously helped CD with his research.
Reeks refers to the verso of the letter, on which he gave the weights of the materials sent to him by CD.
Charles Tookey was employed in the Metallurgical Laboratory of the Royal School of Mines.


Sends weights of three objects (blotting paper, thread, and hair) to within 1/1000 of a grain.

Letter details

Letter no.
Trenham Reeks
Charles Robert Darwin
Sent from
London, Jermyn St, Museum
Source of text
DAR 58.1: 10–11
Physical description
ALS 4pp

Please cite as

Darwin Correspondence Project, “Letter no. 2984,” accessed on 12 September 2023,

Also published in The Correspondence of Charles Darwin, vol. 8