Three companies deployed as skirmishers drove three regiments of Federals without giving ground.

General Johnston retired by the Canton road, and by his order I fell back some 40 miles, to Forest, on Southern Railroad. I again advanced, and the enemy having evacuated Jackson I took possession, and marched through to effect a junction with forces under General Johnston. In the meantime, Brigadier-Generals McNair and Ector, with their brigades, the neighborhood of Jackson, and having assumed command of them also, I effected a junction with Johnston.

The army now under my command, General Johnston having gone to Jackson, numbers some 12,000 men, and, under instructions, I am organizing it, moving leisurely to such points in this section as may furnish water for the troops.

General Loring is at Jackson with his DIVISION, some 6,000 strong.

General Johnston is anxiously awaiting re-enforcements sufficient to advance upon Vicksburg and relieve General Pemberton. Grant has some 60,000 to 80,000 men, and is being strengthened. Our cavalry is deficient in numbers and in other respects.

I sent General Walker across the Big Black yesterday to relieve Yazoo City, but fear that the abandonment of our positions on that river near the Mississippi River, by General Pemberton, will cause the evacuation of that city also before my troops can reach it.

Pemberton, of course, is censured by every one, particularly for making the first fight at Baker's Creek, without awaiting General Johnston, who was marching to join him. He was defeated at Baker's Creek and the Big Black, and lost nearly all of his artillery. It is said that the troops were badly handled by Pemberton, and other hard things are said about him. This we must expect if an officer is unsuccessful. I can form no opinion, as I have no reliable information about the matter.

Vicksburg is completely invested by Grant's army, but we learn from scouts that Pemberton has signally repulsed, with great slaughter to the enemy, three several attempts to storm his defenses. He has provision enough, and, if troops are sent us in time, we can yet save Vicksburg.

We will move as soon as we are strong enough to be effective. Officers, men, and citizens have unbounded confidence in Johnston.

Loring was forced to abandon his field pieces, but secured his horses and harness.

Ferguson's battery is in fine condition, and your son has just left my quarters in excellent health. I have only three batteries, but expect more from Bragg's army.

My command is composed of [W. H. T.] Walker's, [E.] McNair's, [M. D.] Ector's, [J.] Gregg's, [J.] Adams', and my own brigades.

The people, I regret to say, are somewhat desponding, but the presence of Johnston is rapidly restoring confidence.

I have my hands full of work, as the troops left behind many necessary matters, and those engaged at Jackson lost their baggage. My troopsom the cars to the field, and could not return for their baggage.

I will endeavor to write you further at a future day.

Be pleased to present my regards to your brother, Dr. [S.] Choppin, Colonel [A. G.] Rice, and other members of your staff; and permit me again to thank you for many acts of consideration and kindness, and to assure you of my admiration, respect, and high regard.

Very truly and hastily, yours,

S. R. GIST.