SIR,--On the 14th of April I wrote to you, on the presumption that a law respecting the western road had passed the Legislature of Pennsylvania, in the form enclosed by Mr. Dorsey, and which I enclosed to you. I have now received from the Governor an authentic copy of the law, which agrees with that I forwarded to you. You will therefore be pleased to consider the contents of that letter as founded in the certainty of the fact that the law did pass in that form, although not certainly known at that time, and proceed on it accordingly. I shall be in Washington on the 16th and 17th inst., should you have occasion for further communication with me. I salute you with esteem and respect. TO MR. MADISON. MONTICELLO, May 1, 1807. DEAR SIR,--I return you Monroe's, Armstrong's, Harris's, and Anderson's letters, and add a letter and act from Gov. McKean, to be filed in your office. The proposition for separating the western country, mentioned by Armstrong to have been made at Paris, is important. But what is the declaration he speaks of? for none accompanies his letter, unless he means Harry Grant's proposition. I wish our Ministers at Paris, London, and Madrid, could find out Burr's propositions and agents there. I know few of the characters of the new British administration. The few I know are true Pittites, and anti-American. From them we have nothing to hope, but that they will readily let us back out. Whether they can hold their places will depend on the question whether the Irish propositions be popular or unpopular in England. Dr. Sibley, in a letter to Gen. Dearborne, corrects an error of fact in my message to Congress of December. He says the Spaniards never had a single soldier at Bayou Pierre till after 1805. Consequently it was not a keeping, but a taking of a military possession of that post. I think Gen. Dearborne would do well to desire Sibley to send us affidavits of that fact. Our weather continues extremely seasonable, and favorable for vegetation. I salute you with sincere affection. P. S. The pamphlet and papers shall be returned by next post. TO MR. OLIVER EVANS. MONTICELLO, May 2, 1807.