CAIRO, ILL., August 6, 1862-7 p.m.

Major-General HALLECK, General-in-Chief:

The Navy has abandoned Vicksburg, and the fleet of Commodore Davis has united with my force at Helena. This leaves the Arkansas again in the power of the enemy's gunboats, and may allow Hindman to finish his conscription. Commodore Davis is here. He concurs with me in the ability of our gunboats to go up White River, but such a move is inexpedient while the enemy seems to have power to command the mouth of the river. You perceive a wagon movement (which, as your ordered, I immediately commenced) can only extend to White River. It will probably return. Our Missouri friend erroneously apprehended the advance of Price. Your order, I infer, was given supposing our fleet held the mouth of the Arkansas and White Rivers, and that gunboats could not go up the White River, both of which facts do not now exist. To go to Little Rock you perceive is not necessary,and I do assure you, with my train at this season of the year, it is not immediately possible.

To explain. Forage is quite exhausted. Wagons need horses and horses need shoes; all which I am trying to remedy as fast as possible. But the clearing of the Mississippi seems a first necessity, for when I leave the river with most of my force the gunboats, I think, will not keep the river open, and my supplies will be immediately cut off,as the supplies to the gunboats at Vicksburg were cut off. Opening the Mississippi is therefore a condition precedent. If my requisition for boats had been met by the quartermaster, instead of delaying to disprove what I know to be a fact in regard to White River navigation, concurred with me in the necessity of establishing our power on the river and before we depart beyond supporting distance of the fleet, which does not feel safe without our co-operation.

In any and all ways, however, we are your obedient and faithful soldiers.

SAML. R. CURTIS,

Major-General.

SPRINGFIELD, August 6, 1862.

Brigadier General JOHN M. SCHOFIELD, Saint Louis:

I am glad to hear arms are coming. I have given, as a general rule,