WASHINGTON CITY, October 15, 1865.

Bvt. Major General M. C. MEIGS,

Quartermaster-General U. S. Army:

GENERAL: I with pleasure comply with your request before leaving the service by furnishing a concise report of my connection with the department and the events of interest which have transpired under my own orders or observation, and also by making such suggestions as I think may be of service in the future. I must, however, state that owing to the mode of reporting the transactions and auditing the accounts of the Department now required by law and Army Regulations, by which a full analysis of the same cannot be made for from one to two years, it will be impossible at present to give those tabular statements showing the large transactions of the transportation branch of the service, which would be both interesting and instructive, and my report must consequently be general in its character, leaving details and most of the exhibits to be furnished at some future period when peace has given time for a careful examination and classification of the great mass of reports and documents accumulated during the progress of the war. The subject of transportation in the conduct of war has always been one of primary importance, and the application of steam to transportation has perhaps as much modified the art of war as it has the pursuits of peace, and should, through its ability of rmore rapid concentration of troops and supplies at distant points, give greater vigor to a campaign and vast advantage to the party having superiority in this respect. Not only has the world never before seen such vast armies so suddenly and so easily created, but never has it witnessed such rapidity in the transit of those armies for long distances with their vast munitions and supplies. It is now practicable on twenty-four hours' notice to embark at Boston or Baltimore a larger army than those with which Napoleon won some of his most decisive vicotries, and landing within three days at Cairo, 1,200 miles distant, there embark it on transports, and within four days' more time disembark it at New Orleans, 1,000 miles farther, or 2,200 miles form the point of departure. Boats could easily be gathered at Cincinnati, Louisville, and Saint Louis which could within a week precipitate 200,000 troops, with all necessary munitions and supplies, upon Cairo or Memphis. Hence, and from statements of various expeditions hereinafter given, it will be easy to see the great importance of the best possible management of our river and railroad transportation in order to a successful campaign, especially when the theater of war is so expanded as has been the present.

On entering upon the duties to which I was assigned by my superior officer, Major (now Vbt. Major General) Robert Allen, in November, 1861, as chief of rail and river transportation at Saint Louis, my first object was to introduce, as far as possible, such system as should combine uniformity with responsibility and efficiency with economy, no then existing, owing to the confusion generally prevailing at the commencement of the war and especially in the Western Department, it being the period between General Fremont's and General Halleck's administrations. Under general Fremont's orders, the entire river transportation was performed by chartering boats, nearly all of those within the department being so employed, though we then only commanded the river as far south as Cairo. Satisfied, on a cursory examination, that this mode of conducting the service was as wrong in principle as it was extravagant in practice, that a very small proportion of the boats then in service were actually required (many of them being either idle or unprofitable engaged, according to the caprice of officers in command),