Henry E. Davies, Jr., formerly Colonel of the Harris Light, and for some time past in command of the First brigade of Kilpatrick's division, was congratulated to-day by his friends upon his promotion to brigadier-general. No promotion was ever more fitly made, and the "star" never graced a more perfect gentleman or more gallant soldier. The general feeling in the command is, long may he live in the service of his country and for the honor of her flag. _Sunday, September 20._--This morning very appropriate and solemn funeral services were held, conducted by Chaplain Edward P. Roe, in honor of the officers and soldiers of the Harris Light, who were killed in our recent advance to, and skirmishes along, the Rapidan and Robertson Rivers. IMPORTANT RECONNOISSANCE AND RAID. On the morning of the twenty-first, at day-break, an important movement was commenced by Generals Kilpatrick and Buford, while General Gregg remained on the picket lines. The object of the advance was mainly to reconnoitre the position and strength of the enemy, and at the same time to do all the mischief we could. We made a forced march directly upon Madison Court House, meeting but little opposition. The tired troopers rested themselves and their animals at night, preparatory to another early advance. _September 22._--We were early in the saddle, with our steps turned southward in the direction of Orange Court House. The two divisions advanced upon different but nearly parallel roads. We had not proceeded far before messengers from General Buford informed us that, by a rapid movement across the country between the two roads, Kilpatrick might intercept a brigade of the enemy's cavalry, which Buford was engaging and pursuing. The Harris Light had the advance of the division, and we soon came in contact with the retreating Rebel force in a dense oak forest, through which we were compelled to approach the pike by a wood road, which was so narrow as to necessitate our moving in columns of twos. Upon gaining the main road we found the entire force of the enemy advancing with skirmishers deployed, and a battery of light artillery in position, which instantaneously opened upon us with grape and canister. The situation of our regiment was extremely critical and embarrassing. ENGAGEMENT AT LIBERTY MILLS.