Some difficulties have arisen in relation to contracts for the transportation of the mails by railroad and steamboat companies. It appears that the maximum of compensation provided by Congress for the transportation of the mails upon railroads is not sufficient to induce some of the companies to convey them at such hours as are required for the accommodation of the public. It is one of the most important duties of the General Government to provide and maintain for the use of the people of the States the best practicable mail establishment. To arrive at that end it is indispensable that the Post-Office Department shall be enabled to control the hours at which the mails shall be carried over railroads, as it now does over all other roads. Should serious inconveniences arise from the inadequacy of the compensation now provided by law, or from unreasonable demands by any of the railroad companies, the subject is of such general importance as to require the prompt attention of Congress. In relation to steamboat lines, the most efficient remedy is obvious and has been suggested by the Postmaster-General. The War and Navy Departments already employ steamboats in their service; and although it is by no means desirable that the Government should undertake the transportation of passengers or freight as a business, there can be no reasonable objection to running boats, temporarily, whenever it may be necessary to put down attempts at extortion, to be discontinued as soon as reasonable contracts can be obtained. The suggestions of the Postmaster-General relative to the inadequacy of the legal allowance to witnesses in cases of prosecutions for mail depredations merit your serious consideration. The safety of the mails requires that such prosecutions shall be efficient, and justice to the citizen whose time is required to be given to the public demands not only that his expenses shall be paid, but that he shall receive a reasonable compensation. The reports from the War, Navy, and Post-Office Departments will accompany this communication, and one from the Treasury Department will be presented to Congress in a few days. For various details in respect to the matters in charge of these Departments I would refer you to those important documents, satisfied that you will find in them many valuable suggestions which will be found well deserving the attention of the Legislature.