During the sickness which has confined me to my room a great part of the winter, and from which I am still but slowly convalescent, I have occasionally turned my mind to the Florida question which the late demand of the Chevalier Onis has revived. When in Philadelphia last winter, I obtained from his secretary Mr. Heredia, the whole strength of their cause, which I found so weak, that I promised myself an easy victory over all its partizans in this country. It was not until I heard with regret, & astonishment, that Judge Cooper was one of the most zealous, as he is certainly the most able of them, that I dreaded an opposition more formidable than that of the Spanish Embassy. I have not yet seen Judge Coopers essay in the ‘Democratic Press’ of Philadelphia, and am therefore unable to say whether it be as profound as his known learning would lead us to expect. But as the case still appears to me a plain one, I will not abandon its defence, from a natural reluctance to enter the lists with such an adversary, accoutred at all points with various & elegant learning.

As I have none of these advantages, but rely entirely upon the simplicity of the question, I will beg Sir, briefly to state to you the order in which I shall view the subject, & to ask of you some information which your knowledge of the public law will no doubt enable you to give me.  

1. The first proposition upon which the Spanish minister relies, tho’ not stated in his letter to Mr monroe is, that the treaty of St Ildefonso was to take effect upon the performance of a condition precedent, relative to the duke of Parma, which the French Government failed to perform, & that therefore the treaty of St Ildefonso is void.

I do not know how the fact was, as to the non-compliance with this condition. But the treaties of St. Ildefonso & of Paris by which Louisiana was ceded to the U.S., having been published & acted on without any protest on the part of Spain, became a part of the public law which all nations are bound to respect.

Besides, the failure of the condition upon which the treaty of St Ildefonso was to be binding upon Spain, applies with equal force to the acquisition of that part of Louisiana to the west, as to that on the East of the mississippi, & as Spain does not contest our claim pro tanto it is a waiver of the objection to the whole.

2. They contend that the treaty of St Ildefonso conveyed Louisiana to France under the same boundaries with which she held it, after all East of the mississippi except the isle of orleans had been ceded to England by the treaty of 1763. But the words of the treaty ‘et qu’elle avoit lorsque la France la possedait’ cannot by any fair interpretation be confined to the period when France held it with the narrowest limits, more especially as France was at the time of the treaty of St. Ildefonso [1800] the dominant power in Europe, & from its known address in diplomacy would never have suffered such an evasion when it was able to resist it. The obvious1 meaning of the clause is, that Spain ceded to France, every thing which she then held, & that France had at any time held as Louisiana. Now the journal of the Chevalier la Salle shews that the first settlements of the French in Louisiana were on the Ilinois, & then at St. Joseph near the lakes. The first settlements in the south [as will appear from the journal of Messrs. Bienville & Iberville] were at Biloxi & Mobile, both far to the East of the mississippi. They had also a settlement at Alabama at Toulouse, & indeed according to the European usage they claimed all the waters both of the mississippi & of the Alabama.

3. The whole extent of this vast country then, was conveyed to France by the treaty of St. Ildefonso, with the exception of such portions as had been taken from it by previous conventions, which were

1. all East of Rio Perdido by the treaty of Cambray between France & Spain [1714 or 1719.]

2. all which fell within the boundaries of the U.S. at the recognition by Spain of our Independence, which was all north of the 31° N. Lat. between the mississippi and the chatahouchy, & thence all north of the junction of Flint River with the chatahouchy, & the sources of St: Marys.

If this interpretation of the treaty of St. Ildefonso be correct, and these facts be true, the conclusion is irresistible, that all which was ever Louisiana, now belongs to the U.S. except that portion which lies between the Perdido & the sources of St. Marys, south, constituting the present East Florida.

I will beg of you the favor Sir, if it be not giving you too much trouble, to give me any information that may be necessary to support these positions but especially as to the boundary between Louisiana & Florida as fixed by the treaty of Cambray.

I am sorry that others much more capable than I am, from facility of access to all the repositories of public law, are too indifferent to a question of such national concern to employ their time in a work which could not fail to be useful to their country. I have already offered this scheme of defence to George Dallas of Philadelphia, but he shuns the contest. I shall only engage in it, upon the condition that I can draw from your quiver, some better weapons than any that I find in my own.

I beg to be presented with sentiments of regard to Mrs Randolph, and