I received on the 20th. your letter of the 7th. inst. The Agricultura[l] paper to which it refers, being already in print, is of course subject to any further publication, without my consent: And I regard the asking it as a special mark of your politeness; the more so as it was intended to give me an opportunity of rectifying the errors into which I might have fallen. That there may be more of these than have occurred to either of us, is probable and that the passage you have pointed out, may be particularly exposed to unfriendly criticism, your suggestions ought to make me aware. I have not however, if there were time, the means of consulting the most recent works on Chymistry, and adapting what was advanced to the most approved of them. I must leave it therefore as it is; with a wish that if the paper should be inserted in your Agricultural Memoirs, it may be accompanied with whatever notices may be necessary to shew that its errors are those of an Individual only, and no wise chargeable on a defective State of Chymical knowlege in our Country.

It was far from my purpose, to enter into the depths of the question concerning the formation & food of plants. I had in view merely to infer from the vast variety of dissimilar objects in the organized departments of nature, that they could not all be composed of a few ingredients precisely the same in all. I could not reconcile either with a physical possibility, or with the apparent economy of nature, a supposition that these few distinct ingredients, whether designated by the names of elements, atoms, molecules, or gasses, could produce so great a profusion of heterogeneous existences; that they could be indiscriminately fitted for the composition & structure of each of them; and consequently that the entire mass of organizable matter might be converted into a single species of plants, the potatoe for example, and thence exclusively into the human species feeding on it.

It seemed to be more reasonable to distrust the results of Chymistry, or rather the adequacy of its decomposing and discriminating powers; and to suppose that the very few gazeous substances may themselves be further divisible, as a solar ray has been found to be by a prism; that other substances elude altogether the analysing processes, as the gasses formerly did; or that there are other elementary substances, not only undiscovered, but undiscoverable, sufficient in number & variety to form by their combinations with each other, and with those already known, the system before us, with all its diversified organizations & appearances.

In attempting to solve the problem relating to the composition, mechanism, and growth of vegetables, we must either suppose that three four or five elements, simple and immutable in their essence, are susceptible of combinations sufficiently multiplied to produce the vegitable system; or that other and more numerous elements remain to be added to them; or that the vegitable organs possess a transubst[ant]iating power by which one element can be changed into another. Among these alternatives, the first & the last seemed to have least claim to our assent.

I am very sensible, Sir, that I have glided into a train of ideas too hasty and too crude for even a private letter: and that they need an apology much more than was called for by the observations in your letter; which had sufficient interest to recommend them to attention, and the frankness of which could have no other effect than to enhance the respect & esteem of which I tender you assurances.