SIR,--I have lately seen a printed report of the committee of the Canal company of New Orleans, stating the progress and prospects of their enterprize. In this the United States feel a strong interest, inasmuch as it will so much facilitate the passage of our armed vessels out of the one water into the other. For this purpose, however, there must be at least five and a half feet water through the whole line of communication from the lake to the river. In some conversations with Mr. Clark on this subject the winter before last, there was a mutual understanding that the company would complete the canal, and the United States would make the locks. This we are still disposed to do; and so anxious are we to get this means of defence completed, that to hasten it we would contribute any other encouragement within the limits of our authority which might produce this effect. If, for instance, the completion of it within one year could be insured by our contributing such a sum as one or two thousand dollars a month to the amount of twenty thousand dollars, in the whole, we might do it, requiring as a consideration for our justification that the vessels of the United States should always pass toll-free. The object of this letter is to sound the principal members, without letting them know you do it by instruction from us, and to find out what moderate and reasonable aid on our part would be necessary to get a speedy conclusion of the work, and in what form that aid would be most useful, and to be so good as to communicate it to me as soon as the knowledge is obtained by yourself. I should be glad to learn, at the same time, what is the perpendicular height of the top of the levee above the surface of the water in the Mississippi in its lowest state. Five and a half feet below this would be indispensable for our purposes. I salute you with great esteem and respect. TO THE SECRETARY OF THE TREASURY. July 12, 1808. 1. (Peyton Skipwith's letter.) I approve of the proposition to authorize the collector of St. Mary's or Savannah to permit vessels to bring to St. Mary's such supplies as in his opinion are really wanted for the individuals applying, and where he has entire confidence no fraud will be committed. But the vessels should be reasonably proportioned to the cargo. Should this be extended to Passamaquoddy?