From Trenham Reeks   15 November 1860

My dear M^r. 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 M^r. 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 $\frac{1}{1000}$ 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.

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Believe me, Yours very sincerely | Trenham Reeks.