The Report of Mr. HALL, the Postmaster General, gives a gratifying picture of the operations of the Post Office Department. The number of mail routes within the United States at the close of the fiscal year in June last, not including California and Oregon, was 5590: the aggregate length of such routes was 178,672 miles, and the number of contractors employed thereon, 4,760. The annual transportation of the mails on these routes was 46,541,423 miles, at an annual cost of $2,724,436, making the average cost about five cents and eight and a half mills per mile. The increase in the number of inland mail routes during the year was 649; the increase in the length of mail routes was 10,969 miles; and the annual transportation of the year exceeded that of the previous year by 3,997,354 miles, at an increased cost of $342,440. There were, on the 30th of June last, five foreign mail routes, of the aggregate length of 15,079 miles, and the annual price of the transportation thereon, payable by this Department, was $264,506; being an increase of $8814 on the cost of the preceding year. The increase of our mail service for the last fiscal year, over the year preceding, was about 9.4 per cent., and the increase in the total cost was about 12.7 per cent. The number of Postmasters appointed during the year ending June 30, 1850, was 6518. Of that number 2600 were appointed to fill vacancies occasioned by resignations; 233 to fill vacancies occasioned by the decease of the previous incumbents; 562 on a change of the sites of the offices for which they were appointed; 1444 on the removal of their predecessors, and 1979 were appointed on the establishment of new offices. The whole number of post offices in the United States at the end of that year was 18,417. There were 1679 post offices established, and 309 discontinued during the year. The gross revenue of the Department for the year was as follows: From letter postage, including foreign postage, and stamps sold $4,575,663 86 From newspapers and pamphlets 919,485 94 From fines 38 00 From miscellaneous items 3,048 66 From receipts on acc't of dead letters 1,748 40 -------------- $5,499,984 86 Appropriation for franked matter 200,000 00 -------------- Total $5,699,984 86