The report of the Postmaster-General will make known to you the operations of that Department for the past year. It is gratifying to find the revenues of the Department, under the rates of postage now established by law, so rapidly increasing. The gross amount of postages during the last fiscal year amounted to $4,371,077, exceeding the annual average received for the nine years immediately preceding the passage of the act of the 3d of March, 1845, by the sum of $6,453, and exceeding the amount received for the year ending the 30th of June, 1847, by the sum of $425,184. The expenditures for the year, excluding the sum of $94,672, allowed by Congress at its last session to individual claimants, and including the sum of $100,500, paid for the services of the line of steamers between Bremen and New York, amounted to $4,198,845, which is less than the annual average for the nine years previous to the act of 1845 by $300,748. The mail routes on the 30th day of June last were 163,208 miles in extent, being an increase during the last year of 9,390 miles. The mails were transported over them during the same time 41,012,579 miles, making an increase of transportation for the year of 2,124,680 miles, whilst the expense was less than that of the previous year by $4,235. The increase in the mail transportation within the last three years has been 5,378,310 miles, whilst the expenses were reduced $456,738, making an increase of service at the rate of 15 per cent and a reduction in the expenses of more than 15 per cent. During the past year there have been employed, under contracts with the Post-Office Department, two ocean steamers in conveying the mails monthly between New York and Bremen, and one, since October last, performing semimonthly service between Charleston and Havana; and a contract has been made for the transportation of the Pacific mails across the Isthmus from Chagres to Panama. Under the authority given to the Secretary of the Navy, three ocean steamers have been constructed and sent to the Pacific, and are expected to enter upon the mail service between Panama and Oregon and the intermediate ports on the 1st of January next; and a fourth has been engaged by him for the service between Havana and Chagres, so that a regular monthly mail line will be kept up after that time between the United States and our territories on the Pacific. Notwithstanding this great increase in the mail service, should the revenue continue to increase the present year as it did in the last, there will be received near $450,000 more than the expenditures. These considerations have satisfied the Postmaster-General that, with certain modifications of the act of 1845, the revenue may be still further increased and a reduction of postages made to a uniform rate of 5 cents, without an interference with the principle, which has been constantly and properly enforced, of making that Department sustain itself.