In the outset of the business of detentions, I think it impossible to form precise rules. After a number of cases shall have arisen they may probably be thrown into groups and subjected to rules. The great leading object of the Legislature was, and ours in execution of it ought to be, to give complete effect to the embargo laws. They have bidden agriculture, commerce, navigation, to bow before that object, to be nothing when in competition with that. Finding all their endeavors at general rules to be evaded, they finally gave us the power of detention as the panacea, and I am clear we ought to use it freely that we may, by a fair experiment, know the power of this great weapon, the embargo. Therefore, to propositions to carry flour into the Chesapeake, the Delaware, the Hudson, and other _exporting_ places, we should say boldly it is not wanted there for consumption, and the carrying it there is too suspicious to be permitted. In consequence of the letters to the Governors of the flour-importing States, we may also say boldly that there being no application from the Governor is a proof it is not wanting in those States, and therefore must not be carried. As to shuffling of cotton, tobacco, flax seed, &c., from one port to another, it may be some trifling advantage to individuals to change their property out of one form into another, but it is not of a farthing's benefit to the nation at large, and risks their great object in the embargo. The want of these at a particular place should be very notorious to the collector and others, to take off suspicion of illicit intentions. Dry goods of Europe, coal, bricks, &c., are articles entirely without suspicion. I hazard these things for your consideration, and I send you a copy of the letter to the Governors, which may be communicated in form to the collectors to strengthen the ground of suspicion. You will be so good as to decide these cases yourself, without forwarding them to me. Whenever you are clear either way, so decide; where you are doubtful, consider me as voting for detention, being satisfied that individuals ought to yield their private interests to this great public object. TO THE SECRETARY AT WAR. MONTICELLO, May 12, 1808. DEAR SIR,--My journey and two days' detention on the road by high waters, gave me time to reflect on our canal at New Orleans, on which I will therefore hazard some thoughts.