The great mineral wealth of California and the advantages which its ports and harbors and those of Oregon afford to commerce, especially with the islands of the Pacific and Indian oceans and the populous regions of eastern Asia, make it certain that there will arise in a few years large and prosperous communities on our western coast. It therefore becomes important that a line of communication, the best and most expeditious which the nature of the country will admit, should be opened within the territory of the United States from the navigable waters of the Atlantic or the Gulf of Mexico to the Pacific. Opinion, as elicited and expressed by two large and respectable conventions lately assembled at St. Louis and Memphis, points to a railroad as that which, if practicable, will best meet the wishes and wants of the country. But while this, if in successful operation, would be a work of great national importance and of a value to the country which it would be difficult to estimate, it ought also to be regarded as an undertaking of vast magnitude and expense, and one which must, if it be indeed practicable, encounter many difficulties in its construction and use. Therefore, to avoid failure and disappointment; to enable Congress to judge whether in the condition of the country through which it must pass the work be feasible, and, if it be found so, whether it should be undertaken as a national improvement or left to individual enterprise, and in the latter alternative what aid, if any, ought to be extended to it by the Government, I recommend as a preliminary measure a careful reconnaissance of the several proposed routes by a scientific corps and a report as to the practicability of making such a road, with an estimate of the cost of its construction and support. For further views on these and other matters connected with the duties of the home department I refer you to the report of the Secretary of the Interior. I recommend early appropriations for continuing the river and harbor improvements which have been already begun, and also for the construction of those for which estimates have been made, as well as for examinations and estimates preparatory to the commencement of such others as the wants of the country, and especially the advance of our population over new districts and the extension of commerce, may render necessary. An estimate of the amount which can be advantageously expended within the next fiscal year under the direction of the Bureau of Topographical Engineers accompanies the report of the Secretary of War, to which I respectfully invite the attention of Congress.