They were soon exposed to heavy fires of small-arms and of a field battery planted in their front, and they responded well for some time to the volleys of the besiegers; but finally their ranks were thrown into confusion, and they fell back rapidly in rear of our entrenchments. General Buckner continued to encourage his men, feeling that a little time was necessary ot overcome the dispiriting effects of the repulse earlier in the day.

In the mean time the fires of our left wing were heard steadily advancing, driving the enemy back upon his right center. This was referred to with encouraging effect upon General Buckner's division. Artillery fires were kept up against the enemy in his front, and soon afterwards he moved forward with his division to renew the attack. The enemy, being now pressed in front of his center by this advance and on his right flank by the pursuing forces of General Pillow's division, retreated rapidly for some distance towards his left wing; but, receiving heavy reenforcements, the pursuit was checked, and finally the retreating foe made a firm stand, opening from a field battery strongly supported by masses of infantry.

About 1 o'clock an order was given by General pillow recalling our forces to the defensive lines. Our forces having returned, they were ordered to the positions they occupied the day previous, involving a march of over a mile for the troops on the extreme right. The enemy at the same time advanced with his re-enforcements to attack that flank, and by a prompt movement succeeded in effecting a lodgment within the lines just as our exhausted forces arrived.

A vigorous attempt to dislodge him failed, and at length our men, having suffered much, fell back, leaving him in possession of that portion of our defenses. The advantage gained by the enemy placed him in position to assault our right in full force with his fresh troops next morning. Such was the condition of affairs when the darkness of night closed the bloody struggle of the day. In the course of the night General Floyd, Pillow, and Buckner met in council. I was not present.

The following morning, about 3 o'clock, I was told by General Pillow that a surrender had been decided on. He invited me to join himself accepted, and accompanied him to Clarksville and Nashville, where I had the honor to report to you in person.

From information received the strength of the enemy at Donelson was estimated to be about 50,000. Our effective force was about 15,000. The surrender at Fort Donelson made Nashville untenable by the forces under your command. Situated in a wide basin, intersected y a navigable river in possession of the invader; approached from all directions by good turnpike roads and surrounded by commanding hills, involving works of not less than 20 miles in extent, the city could not be held by a force less than 50,000. With all the re-enforcements to be hoped for your army could not be raised to that number before the place would have been attacked by heavy forces of the enemy both by land and water. The alternative was to withdraw to the interior of the State of Tennessee.

'

J. F. GILMER,

Lieutenant-Colonel, and Chief Engineer Western Department.

Colonel W. W. MACKALL,

Asst. Adjt. General Western Department, Decatur, Ala.