Your favor of the 3d was recieved some days ago and I have taken time to make a thorough search among my paper for whatever might relate to Dr Sibley, but to no effective purpose. the part of his correspondence which related to public matters was with the Secy at War. the few letters I have of his, respect matters of curiosity, Indian vocabularies Etc things of that kind. When we acquired Louisiana we were exceedingly uninformed of every thing relating to it. I addressed enquiries to every individual of the country who I thought might give us information, and I remember that I considered that furnished by Dr Sibley as distinguished in it’s value. at the ensuing Congress I communicated the whole to that body, and it was printed and made a large 8vo volume. the originals, and their printed copy, were probably burnt by the British, but the printed copy which I had kept for myself went afterwards to Washington with my library and may there be turned to, it will be found entered in the printed catalogue pa. 104. No 261. under the title of ‘State papers 1793–1812. 36. v. 8vo’ the date of the communication, Nov. 14. 1803. will point to the particular volume. in this will probably be found much of the information recieved from Dr Sibley, which will give an idea of the extent & value of his services to us on that occasion.

With respect to the two articles particularly stated on your letter, I have carefully examined all my papers and letters of the years 1804. and 1805. and do not find the scrip of a pen relative to them. my memory furnishes me with some general recollections on which I can depend as to De la Harpe’s journal; but several of the particulars are too faintly recalled to be depended on. for example, I am not certain whether the correspondence and orders on that subject passed between Govr Claiborne and myself, or the War office and Dr Sibley. my impression, altho faint, is that it was Govr Claiborne who informed me of the existence of that book in the hands of an individual, and that it could be purchased, giving such a description of it’s contents as showed it to be highly important to us in our then uninformed state. I think he had got his information of it from Dr Sibley. we directed the purchase to be made, and that before trusting the original to the mail, a copy should be taken (as I think, but your letter says two and it may be so) and sent by successive mails. they were safely recieved, and I have believed the cost of the whole had been promptly reimbursed, either to Claiborne or Dr Sibley; through whose agency it was obtained. the importance of the work consisted in this. De la Harpe was in some considerable office in the government of Louisiana, and kept a private and regular journal of the public transactions. the French considered the Rio bravo as the Western boundary of Louisiana, but the Spaniards claimed indefinitely to the East of that river. the French and Spanish neighboring governors, with certain mercantile associates, entered into a Contraband commerce, the former furnishing French merchandise and recieving from the latter hard dollars in exchange. but the distance between N. Orleans & the Rio bravo occasioned inconveniences and difficulties, and therefore the French Governor winked at the Spaniard’s taking a small post at Nacogdoches, & made his reclamations so faintly as not to disturb the post. I cite these transactions by memory, but believe without material error. when we acquired Louisiana, we considered it as extending to the Rio Bravo, and so Bonaparte declared to our Commrs and that he should have taken possession to that extent. but Spain, under color of the corrupt foothold she had got at this, and one or two other small posts, claimed the country against us on the ground of possession. this journal of De la Harpe clearly proved how fraudulently it had been obtained, and was therefore of the utmost importance to us. hence our anxiety to guard against it’s loss by having it copied and trusted to different mails. the original being lodged in the office of the Secy of state, I retained a copy in my office to be recurred to in preparing instructions for our minister at Madrid. when I removed from Washington this was inadvertently packed with my own books & papers, and not attended to until the burning of the public records at Washington brought the thing to my mind. I immediately sent the copy to the Secretary of state, in whose office it doubtless now is, and will prove that it’s importance justified the price it cost us.

Of the other transaction respecting the purchase of horses Etc to bring a party of Indians to Washington, I have not the slightest trace either in writing or recollection. to the great value which was set on Dr Sibley’s service, by the administration of that day I bear testimony willingly as an act of duty and of truth.

I am sorry that the decay of my memory does not permit me to offer any thing further, and pray you to be assured of my great respect & esteem

Th: Jefferson