It is proper to add that there is now due to the Treasury for the sale of public lands $22,996,545. In bringing this subject to view I consider it my duty to submit to Congress whether it may not be advisable to extend to the purchasers of these lands, in consideration of the unfavorable change which has occurred since the sales, a reasonable indulgence. It is known that the purchases were made when the price of every article had risen to its greatest height, and the installments are becoming due at a period of great depression. It is presumed that some plan may be devised by the wisdom of Congress, compatible with the public interest, which would afford great relief to these purchasers. Considerable progress has been made during the present season in examining the coast and its various bays and other inlets, in the collection of materials, and in the construction of fortifications for the defense of the Union at several of the positions at which it has been decided to erect such works. At Mobile Point and Dauphin Island, and at the Rigolets, leading to Lake Pontchartrain, materials to a considerable amount have been collected, and all the necessary preparations made for the commencement of the works. At Old Point Comfort, at the mouth of the James River, and at the Rip-Rap, on the opposite shore in the Chesapeake Bay, materials to a vast amount have been collected; and at the Old Point some progress has been made in the construction of the fortification, which is on a very extensive scale. The work at Fort Washington, on this river, will be completed early in the next spring, and that on the Pea Patch, in the Delaware, in the course of the next season. Fort Diamond, at the Narrows, in the harbor of New York, will be finished this year. The works at Boston, New York, Baltimore, Norfolk, Charleston, and Niagara have been in part repaired, and the coast of North Carolina, extending south to Cape Fear, has been examined, as have likewise other parts of the coast eastward of Boston. Great exertions have been made to push forward these works with the utmost dispatch possible; but when their extent is considered, with the important purposes for which they are intended--the defense of the whole coast, and, in consequence, of the whole interior--and that they are to last for ages, it will be manifest that a well-digested plan, founded on military principles, connecting the whole together, combining security with economy, could not be prepared without repeated examinations of the most exposed and difficult parts, and that it would also take considerable time to collect the materials at the several points where they would be required.