HEADQUARTERS Fifteenth ARMY CORPS, Camp before Vicksburg, April 28, 1863.

Major General FRED. STEELE, Comdg. First DIVISION, Milliken's Bend:

DEAR GENERAL: The Choctaw has arrived, and, in pursuance of General Grant's wishes, founded on good policy, I shall to-morrow take ten of General Blair's regiments and proceed up the Yazoo, to make a diversion in favor of Grant's move on Grand Gulf. We will probably spend to-morrow night near our old Chickasaw Bayou, and the move up close to Haynes' Bluff.

We must do all that is possible to make the enemy believe that the movement is a real attack, though it would be had management to attempt a lodgment here and at Grand Gulf, as the enemy could fall on one or the other.

If by a diversion at Haynes' we enable Grant to make a safe foothold at the mouth of Big Black, he can the renew our old plan by moving on the Jackson road, and then we should make a real attack on Haynes', but until we know that Grant has secured a base at Grand Gulf, it would be bad war for us to make a foothold on the Yazoo. We should hold our forces in reserve to re-enforce Grant, or to operate after we know that Grant is able and intends to move inland from Grand Gulf.

While I am up Yazoo, give your thoughts to covering Richmond and improving that road. We may float provisions back from Richmond, but I feel assured all the stores from here to General Grant must pass in wagons over a very precarious road; therefore improve it as much as possible. At least two regiments should be employed all the time on the bad places.

Tuttle will make the road from his camp to Richmond along Walnut Bayou, in no way interfering with your road. Colonel Bingham, Grant's chief quartermaster, should arrange for the trains. Should any news come from Grant, dispatch it to me, up Yazoo, day or night, and keep Grant advised of all passing events, and of what you hear up Yazoo. As soon as the cavalry arrives, keep at least one regiment north and WEST of Richmond. We must cover that good from the direction of Tensas.

Condit Smith will be my chief quartermaster, and will see you daily.

Yours, truly,
W. T. SHERMAN.

SPECIAL ORDERS,
HDQRS. Fifteenth ARMY CORPS, Number 96.
Camp near Vicksburg, April 28, 1863.

I. In compliance with instructions from Major-General Grant, a combined gunboat and army expedition will be made up the Yazoo, for the purpose of diverting the attention of the enemy from the movements now in progress below Vicksburg. This demonstration will be made as soon as the gunboat Choctaw, hourly expected, has arrived.

II. The corps quartermaster, lieutenant Colonel J. Condit Smith, will provide ten good steamboats, and have them at the lower landing, near these headquarters, by to-morrow morning.

III. General F. P. Blair will detail ten good regiments of his DIVISION to be ready with three days' rations, 60 rounds of ammunition, and in light marching order, ready to embark promptly on a signal of two guns from Hart's battery, which will be fired as soon as notice is received that the gunboats are ready.