ALEXANDRIA, September 1, 1864.

(Received 2 a. m. 2nd.)

Colonel TAYLOR,

Assistant Adjutant-General:

COLONEL: We have information that the rebels made three attacks on Falls Church; the first last night, another this morning, them at 12 o'clock to-day; our loss, one man and one horse captured. I have sent what cavalry I have to re-enforce my picket-line, thinking they may attack them to-night.

H. H. WELLS.

HEADQUARTERS CAVALRY BRIGADE,
Near Fort Buffalo, Va., September 1, 1864.

Lieutenant Colonel J. H. TAYLOR,

Chief of Staff and Assistant Adjutant-General:

COLONEL: I have the honor to report that last night at about 10.30 o'clock one of our picket-posts was attacked near this camp. The attacking party was driven off, however, which the loess to the rebels of one horse, and, it is believed, one man wounded. About the same hour the picket-posts on the Braddock road and on the road to Falls Church and Annandale were attacked simultaneously and driven in. This morning 6 a. m. of our pickets about half a mile west of the village of Falls Church was attacked and one vedette capture. Late to-day two of picket-posts between here and Annandale were attacked at about the same time by a force of between twenty an thirty men; 5 men were captured and 7 horses, while men escaped. At about the same hour the picket-post on the Little River pike toward Fairfax Court-House from Annandale was attacked and 1 sergeant and a horse were wounded, 2 men and 3 horses captured. In consequence of these continued attacks I have strenghend the picket-posts to one corporal and four men each, and have dismounted the entire line, with the exception of the non-commissioned officers at each picket station. They are directed to build a crib work of fallen trees to intrench themselves by day and to prevent being charged over by mounted men, and at night the directions are not the same as I have always given-that after dark the vedette should be stationed near the road, concealed, and the rest of the picket moved to some point near him within 200 yards, also concealed. A force of 100 men has been sent out from the Sixteenth New York, divided into two parties, with directions to examine the country in our vicinity. One hundred men from the same regiment were also sent to Annandale to remain several days, that a more effective stockade might be completed there.

Very respectfully, your obedient servant,

H. M. LAZELLE,

Colonel Sixteenth New York Cavalry, Comdg. Cavalry Brigade.

HDQRS. DEPARTMENT OF WASHINGTON, 22ND ARMY CORPS,
Washington, D. C., september 1, 1864.

Colonel LAZELLE,

Commanding near Falls Church:

I have reliable information that Moshby is still lying in the woods din front of your lines and expects to make an attack to-night somewhere