HEADQUARTERS WESTERN DEPARTMENT,
Bowling Green, Ky., January 22, 1862.

General S. COOPER,

Adjutant and Inspector-General:

SIR: I have ordered Major-General Hardee to detach 8,000 troops, of infantry, artillery, and cavalry, to Russellville, and the movement is now going on. The infantry and artillery, with baggage, camp equipage, subsistence, &c., by railroad. The wagon train unloaded and artillery horses, guarded by the cavalry, will move on the common road.

The enemy have moved from Calhoun and Rumsey, on Green River, to South Carrollton, and General Smith, commanding enemy's forces on the Tennessee, turned yesterday from Murray towards Pine Bluff, on Tennessee River, 10 miles below Fort Henry.

General Polk had ordered a movement of 1,000 cavalry and two regiments of infantry towards the rear of the enemy. The badness of the roads on the route to Paris and the movement on his rear has made him relinquish his march to the railroad at Paris, which it is presumed he desired to cut before investing Forts Henry and Donelson.

The roads can only be traveled over with great difficulty in most localities on account of the great quantity of rain which has fallen, but should the ground freeze, the force which is going to Russellville will seize the first favorable opportunity to attack the enemy at South Carollton, unless a movement in force up the Cumberland should make it necessary to go to the support of Clarksville. At Russellville, 28 miles hence, they will be in a position to act effectively in either direction.

I will send to Tilghman at Fort Henry two regiments of volunteers from Henderson Station, 15 miles from Jackson, Tenn. (on the route from Humboldt to Corinth), so soon as they receive their arms, which are now ready for them at Jackson.

If the Burnside expedition goes elsewhere than New Orleans or on the coast of that region, troops may temporarily be spared from New Orleans. General Lovell and the Governor, I understand in that even, would be willing to send them. I hear of no movement of the enemy on my front here.

I have just received a telegram from General Hindman, commanding the advance from this position, announcing the defeat and death of General Zollicoffer at Webb's Cross-Roads, on the road from his position to Columbia. I inclose a copy of the telegram. If my right is thus broken as stated, East Tennessee is open to invasion, or if the plan of the enemy be a combined movement upon Nashville, it is in jeopardy, unless a force can be placed to oppose a movement from Burkesville (100 miles from Nashville) towards Nashville. Movements on my left, threatening Forts Henry, Donelson, and Clarksville, have, I do not doubt, for their ultimate object the occupation of Nashville. I have already detached 8,000 men to make Clarksville secure and drive the enemy back, with the aid of the force at Clarksville and Hopkinsville. But to make another large detachment towards my right would leave this place untenable. The road through this place is indispensable to the enemy to enable them to advance with their main body. They must have river or railroad means of transportation to invade with a large force. While it is of vital importance to keep back the main body, it is palpable this great object cannot be accomplished if detachments can turn my position and attack and occupy Nashville and the interior of the State, which it is the special object to defend.

A reserve at Nashville seems now absolutely necessary to enable me to maintain this position. A successful movement of the enemy on my