As stated in my letter of yesterday, I deem it important that Loudoun County should be occupied immediately; but much, very much, has been already lost by a failure of some troops to occupy Harper's Ferry and Point of Rocks.

My pickets extend to within three miles of the Point of Rocks, but with my present force I cannot advance them a mile with safety, and can only justify my present position by constant activity and watchfulness, and by keeping thee troops under my command worked as constantly as troops can bear.

Half a regiment at Point of Rocks, and the same force at a point opposite Harper's Ferry (if it be not deemed advisable by the general in command at Williamsport to occupy the Ferry itself), would relieve me from great anxiety, and would have saved much uncertainty among the citizens of Virginia and Maryland.

When I pushed forward my posts to Monocacy and Noland's Ferry I supposed that United States troops in some force had certainly occupied the abandoned important points within twenty-five miles of them. We cannot control the Potomac without holding all the points I do, and not with safety and certainty without occupying those of Harper's Ferry or Knoxville and Point of Rocks.

The inclosed appeal of a Virginia I believe to be genuine,and I have no doubt many have been forced into the ranks of the enemy since my arrival here.

Yesterday the opposing pickets at Conrad's Ferry met in the middle of the river, shook hands, and drank each other's health. The Virginia picket men said they did not wish to fight, but "wanted to go home."

With a little more force, and a slight co-operation on the part of General Cadwalader or General Patterson, I could move forward with safety and success. I cannot do so, however, until Harper's Ferry is occupied by somebody and its position understood.

The health of the command remains excellent and the spirits good. An order to cross the river would be received with enthusiasm.

Very respectfully, I am,colonel, your most obedient servant,

CHAS. P. STONE,

Colonel Fourteenth Infantry, Commanding Expedition.

Lieutenant Colonel E. D. TOWNSEND,

Assistant Adjutant-General, Headquarters of the Army

POOLESVILLE, June 24, 1861-8 p.m.

COLONEL: I left camp at midnight last night on a reconnaissance up the river Potomac, accompanied by Captain Wm. S. Abert, A. A. A. G., and Captain Stewart, A. D. C., with an escort of a dozen cavalry, having communicated all my plans of operations up to that time to Colonel F. E. Patterson, First Pennsylvania Regiment, and leaving him in command; passed the extreme pickets of my command at 3 a.m. to-day, and arrived about daybreak at the village-Point of Rocks, Md.

As you are already aware, the bridge across the Potomac has been burned by the enemy. I found that the enemy had a picket of five men watching at the Virginia end of the burned bridge. At Point of Rocks I learned that there were no troops on this side of the river above, and dispatched Captain Abert, with two men on a hand-car, to a point opposite Harper's Ferry. Captain Abert returned at 1.45 p.m., and reported that he had visited Sandy Hook, opposite Harper's Ferry, where he was