I write this merely as a way bill. The Orange post arrives at Charlottesville on Tuesday morning about 10. aclock and returns in half an hour. The Richmond post arrives in Charlottesville on Tuesday evening and returns on Friday morning. I wish to know the difference this makes in the conveyance of a letter to Philadelphia. I therefore write this by the Orange post, and will write such another by that of Richmond, and pray you to note to me the days on which you recieve both.—Your favor of Nov. 16. came to hand the 2d. inst. Our militia are returning it is said, without having been to Detroit. Where then have they been? The explanation of this phaenomenon is ardently wished here. Adieu. Yours affectionately.