DEAR SIR,--Dr. Bollman, on his arrival here in custody in January, voluntarily offered to make communications to me, which he accordingly did, Mr. Madison also being present. I previously and subsequently assured him, (without, however, his having requested it,) that they should never be used _against himself_. Mr. Madison on the same evening committed to writing, by memory, what he had said; and I moreover asked of Bollman to do it himself, which he did, and I now enclose it to you. The object is, as he is to be a witness, that you may know how to examine him, and draw everything from him. I wish the paper to be seen and known only to yourself and the gentlemen who aid you, and to be returned to me. If he should prevaricate, I should be willing you should go so far as to ask him whether he did not say so and so to Mr. Madison and myself. In order to let him see that his prevarications will be marked, Mr. Madison will forward you a pardon for him, which we mean should be delivered previously. It is suspected by some he does not intend to appear. If he does not, I hope you will take effectual measures to have him immediately taken into custody. Some other blank pardons are sent on to be filled up at your discretion, if you should find a defect of evidence, and believe that this would supply it, by avoiding to give them to the gross offenders, unless it be visible that the principal will otherwise escape. I send you an affidavit of importance received last night. If General Wilkinson gets on in time, I expect he will bring Dunbaugh on with him. At any rate it may be a ground for an arrest and commitment for treason. Accept my friendly salutations, and assurances of great esteem and respect. TO MR. DE LA COSTE. WASHINGTON, May 24, 1807.