Much has been accomplished during the year in aid of science and to increase the sum of general knowledge and further the interests of commerce and civilization. Extensive and much-needed soundings have been made for hydrographic purposes and to fix the proper routes of ocean telegraphs. Further surveys of the great Isthmus have been undertaken and completed, and two vessels of the Navy are now employed, in conjunction with those of England, France, Germany, and Russia, in observations connected with the transit of Venus, so useful and interesting to the scientific world. The estimates for this branch of the public service do not differ materially from those of last year, those for the general support of the service being somewhat less and those for permanent improvements at the various stations rather larger than the corresponding estimate made a year ago. The regular maintenance and a steady increase in the efficiency of this most important arm in proportion to the growth of our maritime intercourse and interests is recommended to the attention of Congress. The use of the Navy in time of peace might be further utilized by a direct authorization of the employment of naval vessels in explorations and surveys of the supposed navigable waters of other nationalities on this continent, especially the tributaries of the two great rivers of South America, the Orinoco and the Amazon. Nothing prevents, under existing laws, such exploration, except that expenditures must be made in such expeditions beyond those usually provided for in the appropriations. The field designated is unquestionably one of interest and one capable of large development of commercial interests--advantageous to the peoples reached and to those who may establish relations with them. Education of the people entitled to exercise the right of franchise I regard essential to general prosperity everywhere, and especially so in republics, where birth, education, or previous condition does not enter into account in giving suffrage. Next to the public school, the post-office is the great agent of education over our vast territory. The rapidity with which new sections are being settled, thus increasing the carrying of mails in a more rapid ratio than the increase of receipts, is not alarming. The report of the Postmaster-General herewith attached shows that there was an increase of revenue in his Department in 1873 over the previous year of $1,674,411, and an increase of cost of carrying the mails and paying employees of $3,041,468.91. The report of the Postmaster-General gives interesting statistics of his Department, and compares them with the corresponding statistics of a year ago, showing a growth in every branch of the Department.