I think Sherman has entirely overestimated Granger's forces and underestimated the difficulty of passing Mobile and ascending the Alabama some 150 or 200 miles. Possibly something of the kind might have been effected if A. J. Smith's column had moved on Selma or Montgomery; but I now Learn from Sherman that he was ordered to strike the Tennessee at Eastport or Decatur. It will not do to attempt too many things at once with our rapidly diminishing armies. If Canby weakens the line of the MISSISSIPPI too much to re-enforce Granger, Kirby Smith may cross and re-enforce Hood. I fear that as it is he will send small parties across to meet at some place of rendezvous and then march to Atlanta.

General Canby and Admiral Farragut both understand that the main object of their operations is to assist Sherman, and I think it will be better to let them work out the problem as circumstances may require rather than to embarrass them with orders based on a supposed state of things which may be essentially different when the orders are received.

I have directed General Canby to permit no more exchange of prisoners of war. That part of the cartel which authorizes commanders to exchange on the field troops just captured, man for man, has been considered heretofore as still in effect. I do not see any objection to it, as it can give no advantage to either party and saves our men from barbarous treatment by the rebels. To exchange their healthy men for ours who are on the brink of the grave from their hellish treatment, of course gives them all the advantage; nevertheless it seems very cruel to leave our men to be slowly but deliberately tortured to death, but I suppose there is no remedy at present.

Horses and men for the Second Cavalry DIVISION are being sent down as rapidly as possible. The 100-days's men in WEST Virginia are nearly all discharged. That country is nearly defenseless. The people of that country are in a panic about rebel raids and beg for troops. I have none to send them, and must leave it to Sheridan to keep the enemy occupied.

General Heintzelman reports of the condition of affairs in his department. He is firmly of opinion that the plots of the Copperheads to release the rebel prisoners were frustrated only by sending additional guards, and that such attempts will be made at the earliest favorable opportunity.

At the request of the Governor of Colorado, I telegraphed to General Rosecrans to send the regiment of Colorado cavalry, now at Kansas City, to operate against the hostile Indians on the plains and to protect the overland mail route, but the replied, as usual, that he could not spare any troops. The authorities of Colorado and the Post-Office and Interior Department are very urgent for more troops in that direction, but it is impossible to give them.

Very respectfully, your obedient servant,

H. W. HALLECK,

Major-General and Chief of Staff.

NASHVILLE, TENN., August 27, 1864 - 5. 25 p. m.

(Received 10 p. m.)

Honorable EDWIN M. STANTON, Secretary of War:

After conference with many of our Union men, and especially Honorable Horace Maynard and Parson Brownlow, all are of opinion that it would aid materially in a military point of view, as well as in restoring