Numbers 1. Reports of Colonel John P. Slough, First Colorado Infantry.

KOZLOWSKI'S RANCH, March 29, 1862.

COLONEL: Learning from our spies that the enemy, about 1,000 strong, were in the Apache Canon and at Johnston's Ranch beyond, I concluded to reconnoiter in force, with a view of ascertaining the position of the enemy and of harassing them as much as possible; hence left this place with my command, nearly 1,300 strong, at 8 o'clock yesterday morning. To facilitate the reconnaissance I sent Major J. M. Chivington, First Regiment Colorado Volunteers, by a road running to the left of the canon and nearly parallel thereto, with about 430 officers and picked men, with instructions to push forward to Johnson's. With the remainder of the command I entered the canon, and had attained but a short distance when our pickets announced that the enemy was near and had taken position in a thick grove of trees, with their line extending from mesa to mesa across the canon, and their battery, consisting of four pieces, placed in position. I at once detailed a considerable force of flankers, placed the batteries in position, and placed the cavalry - nearly all dismounted - and the remainder of the infantry in position to support the batteries.

Before the arrangement of my forces was completed the enemy opened fire upon us. The action began about 10 o'clock and continued until after 4 p. m. The character of the country was such as to make the engagement of the bushwhacking kind. Hearing of the success of Major Chivington's command, and the object of our movement being successful, we fell back in order to our camp. Our loss in killed is probably 20, including Lieutenant Baker, or Company I, Colorado Volunteers; in wounded probably 50, including Lieutenant Chambers, of Company C, Colorado Volunteers, and Lieutenant McGrath, U. S. Army, who was serving with Captain Ritter's battery; in missing probably 30. The enemy's loss is in killed from 40 to 60 and wounded probably over 100. In addition we took some 25 prisoners and rendered unfit for service three pieces of their artillery. We took and destroyed their train of about 60 wagons, with their contents, consisting of ammunition, subsistence, forage, clothing, officers' baggage, &c. Among the killed of the enemy 2 majors, 2 captains and among the enemy made three attempts to take our batteries and were repelled in each with severe loss.

The strength of the enemy, as received from spies and prisoners, in the canon was altogether some 1,200 or 1,300, some 200 of whom were at or near Johnson's Ranch, and were engaged by Major Chivington's command.

The officers and men behaved nobly. My thanks are due to my staff officers for the courage and ability with which they assisted me in conducting the engagement.

As soon as all the details are ascertained I will send an official report of the engagement.

Very respectfully,

JNO P. SLOUGH,

Colonel, Commanding Northern Division, Army of New Mexico.

Colonel E. R. S. CANBY,

Commanding Department of New Mexico.