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 1^lb of each kind w^d be sufficient; but you had better send full 1 lb. I sh^d. 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 1^lb 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