My dear D^r. Frankland

Some time ago you were so good as to help me by analysing some water in which Pelargonium leaves had been immersed, & in which you found a considerable quantity of potassium.¹ You were at the same time so kind as to offer further assistance in the matter.² Would you allow my son to send one or two bottles of water for analysis? In order that the experiments may be of more value, an estimation of the potassium or of the soluble ash in the leaves used, ought to be made. This would of course considerably increase the work of analysis, but if it could be managed it would certainly add to the interest of the results.³

My son will make a considerable number of experiments of this kind during the spring & summer, which would entail more analysis than I could possibly ask you to undertake, & it would therefore be convenient to know of some trustworthy analyst who would professionally undertake such work. If you can recommend any one to me I shall be grateful; & we could employ him at once without troubling you if your assistants are especially busy just now, or if it is in any way in the least inconvenient to you to untake any analysis for us at present.

Pray excuse me for troubling you again & believe me | Yours very sincerely | Charles Darwin