WASHINGTON, D. C., September 26, 1863.

Major General O. O. HOWARD,

Commanding Eleventh Corps:

GENERAL: Major-General Hooker directs me to say, that you will proceed with your command to Nashville, Tenn. from thence, in the absence of any further instructions, you will proceed toward Chattanooga.

Your destination will not be made public,but you are at liberty to give the impression to your command that you are going toward Mobile.

The long journey by rail will require from yourself and every officer of your command the utmost vigilance and energy to prevent any disorganization,and, most especially, desertion. To guard against this, you will institute the strictest responsibility upon every officer of your command, and the general will hold you responsible therefor.

Guards for each car should be regularly mounted, and no soldier permitted during the journey to leave sight of the train. The failure of any officer to take his command through, will be considered sufficient reason to recommend his dismissal. The lack of constant energy and vigilance will be inexcusable.

While the troops are en route be care and cleanliness of their arms and equipments must not be neglected.

The artillery horses will be apt to suffer unless the attention of the officers of batteries is given to their care and comfort, seeing that they are regularly watered and fed.

The following named officers, assistant quartermaster of volunteers on special duty on General Hooker's staff, are stationed at points along the route to facilitate and expedite the dispatch of the trains and troops, viz: Colonel Thomas A. Scott, Louisville to Nashville; Captain J. B. Fort at Wheeling; Capts. Lewis M. Cole, William P. Smith, J. Perry Willard, Alexander Diffey. The points at which these officers are stationed will, if you deem it necessary, be given you by J. W. Garrett, esq., president Baltimore and Ohio Railroad at Baltimore.

These officers have been instructed to put your command through in advance of any other business, and special orders from the Secretary of War provide for their taking any trains, cars, rolling stock, or railroads for that purpose.

You will allow no officer or commander to interfere with the progress of your column.

Your route will be, via Baltimore and Ohio Railroad, Wheeling, Columbus, Dayton, Indianapolis, and Louisville.

You must not permit day officer of any grade to leave his command, or be absent from his proper duty on the route.

Headquarters, 248 F Street, Washington, until Monday a.m., 28th, thence by the most expeditious route via Cincinnati, Louisville, and Nashville.

Please see telegram of September 24 for further details of instructions.

DANL. BUTTERFIELD,

Major-General, Chief of Staff.