SIR,--A returning express gives me an opportunity of acknowledging the receipt of your letters of November 12th, December 9th, 10th, 14th, 18th, 25th, 26th, and January 2d. I wrote to you January 3d, and through Mr. Briggs, January 10th. The former being written while the Secretary at War was unable to attend to business, gave you the state of the information we then possessed as to Burr's conspiracy. I now enclose you a message, containing a complete history of it from the commencement down to the eve of his departure from Nashville; and two subsequent messages showed that he began his descent of the Mississippi January 1st, with ten boats, from eighty to one hundred men of his party, navigated by sixty oarsmen not at all of his party. This, I think, is fully the force with which he will be able to meet your gun-boats; and as I think he was uninformed of your proceedings, and could not get the information till he would reach Natchez, I am in hopes that before this date he is in your possession. Although we at no time believed he could carry any formidable force out of the Ohio, yet we thought it safest that you should be prepared to receive him with all the force which could be assembled, and with that view our orders were given; and we were pleased to see that without waiting for them, you adopted nearly the same plan yourself, and acted on it with promptitude; the difference between yours and ours proceeding from your expecting an attack by sea, which we knew was impossible, either by England or by a fleet under Truxton, who was at home; or by our own navy, which was under our own eye. Your belief that Burr would really descend with six or seven thousand men, was no doubt founded on what you knew of the numbers which could be raised in the Western country for an expedition to Mexico, _under the authority of the government_; but you probably did not calculate that the want of that authority would take from him every honest man, and leave him only the desperadoes of his party, which in no part of the United States can ever be a numerous body. In approving, therefore, as we do approve, of the defensive operations for New Orleans, we are obliged to estimate them, not according to our own view of the danger, but to place ourselves in your situation, and only with your information. Your sending here Swartwout and Bollman, and adding to them Burr, Blannerhassett, and Tyler, should they fall into your hands, will be supported by the public opinion. As to Alexander, who is arrived, and Ogden, expected, the evidence yet received will not be sufficient to commit them. I hope, however, you will not extend this deportation to persons against whom there is only suspicion, or shades of offence not strongly marked. In that case, I fear the public sentiment would desert you; because, seeing no danger here, violations of law are felt with strength. I have thought it just to give you these views of