Major General F. Steele has been appointed by General Grant to the command of the forces in the Arkansas expedition to start from Helena. I have directed General Prentiss, and General Steele as soon as he arrived at Helena, to open communication with you, and to rendezvous at Clarendon,making that point the temporary points of supply for the entire expedition; thence to move in conjunction with you open Little Rock. He will have 6,000 good infantry and four batteries. I have also directed him to ascertain whether the Arkansas is navigable, and, if so, to select some proper point on that river as his future base of supplies. The extreme dryness of the country between Clarendon and Little Rock will render it necessary that trains in passing it should be as light as possible. I am very happy to have ascertained you whereabouts, but regret that you did not find it practicable to strike Jacksonport on your way down.

A movement upon Little Rock will undoubtedly call Marmaduke's force down to join Price, and your force,united with the infantry from Helena, is more than sufficient to punish severely all the possible force in Arkansas.

So much of the Department of the Tennessee as is north of the Arkansas River has, by General Grant, been attached to this corps (the Sixteenth). The boundaries are very undefined,but I very confidently rely ;upon the abandonment of all minor considerations and a full co-operation of the two commands.

I have the honor to be, general, very respectfully, your obedient servant,

S. A. HURLBUT,

Major-General.

HEADQUARTERS SIXTEENTH ARMY CORPS, Memphis, Tenn., July 31, 1863.

Major General FRED. STEELE, Helena, Ark.:

GENERAL: Major General U. S. Grant having assigned you to the command of the expedition against Price from Helena, has also desired me to give you instructions. I learn from Davidson, who is now at Wittsburg,that the rebel force has divided. Seven regiments of infantry and some cavalry under Marmaduke have established themselves at Jacksonport. Price, with the remainder of the force,is a little Rock, fortifying. I cannot estimate Price's command at more than 6,000 or 7,000 men. This I think a full estimate, unless he has been re-enforced by Kirby Smith,which I doubt. Davidson himself has about 5,000 mounted men. With Kimball's division, and such as can be taken from the Helena command, you will have 5,000 infantry and four batteries. The union of the two forces will give you a command competent to crush out the entire rebel force in Arkansas. Davidson is about to move for Clarendon, on White River, a point easily accessible by boats at present stage of water. This should be the point of rendezvous for the entire force,and the temporary depot of supplies. If the Arkansas is in navigable stage, another point as high up as you can arrive with boats should be selected as a future depot. These questions must be intrusted to you to determination from better local knowledge than I can have since the short period to which I have been assigned to this duty. I am informed that the country between Clarendon and Little Rock is one of extreme difficulty, principally for lack of water and the peculiarly flinty character of the surface rock. In this view, if a route nearer the Arkansas