JUNE 2, 1862-5.25 a.m.

Brigadier-General HUMPHREYS, or

General MARCY,

Chief of Staff:

I ascended at 4.45 this a.m. Found the enemy in full force opposite this point, with their horses harnessed to their artillery. I observed their movements for half an hour; saw mounted pickets to the extreme left of the large field opposite the point where we are preparing a crossing. To the right, opposite Mechanicsville, the enemy have two large camps, and all along their line there are appearances of lively movements.

In fifteen minutes from the time of my ascent a battery of six guns left the farther side of the field, on the New Bridge road, and came to the heights opposite here and covered themselves in the woods, just one mile and three-quarters from this point. I am confident from the present movements that they intend to intercept our crossing the river. The wearther at present, is calm, and a good opportunity for some officer to ascend in the Mechanicsville balloon before the storm, which I think is near at hand. I would suggest Major Webb, as he is accustomed to the balloon.

Your very obedient servant,

T. S. C. LOWE,

Chief Aeronaut.

JUNE 2, 1862-10.15 a.m.

Brigadier-General HUMPHREYS, or

General MARCY,

Chief of Staff:

The enemy remain quiet and in the same position as reported at 8.15. Large numbers are at work throwing up earth, as before, opposite General Smith's headquarters.

Lieutenant-Colonel Palmer could not stand an ascension owing to vertigo.

T. S. C. LOWE,

Chief Aeronaut.

McCLELLAN'S HEADQUARTERS, June 3, 1862.

Professor LOWE:

It is reported that the enemy in force is advancing on our troops to the left, in front of Sumner and Heintzelman. Please make an ascension as soon as practicable and inform me what you discover in that direction, and make frequent ascensions afterward.

R. B. MARCY,

Chief of Staff.

DOCTOR-GAINES" HOUSE, June 3-2.45 p.m.

Brigadier-General MARCY,

Chief of Staff:

Just as I received your dispatch General Barnard arrived and remained up about twenty minutes. I have just descended myself. I could see no additional troops at the point you inquire about. There have been troops for the past three or four days on the New Bridge road about one mile beyond Doctor Garnett's house or red brick house opposite here, and daily moving about in regiments forward and back as a picket force. I can discover no new movements of the enemy to-day.

T. S. C. LOWE,

Chief Aeronaut, Army of the Potomac.

General Barnard made very frequent ascensions during the whole time our army lay before Richmond, and from observations thus taken he was better enabled to locate earth-works, &c., of which many were constructed.

The following are dispatches without dates, which I take the liberty of adding, as they were accidentally omitted from the copies I retained.

Before the battle of Fair Oaks:

Brigadier General A. A. HUMPHREYS,

Chief of Topographical Engineers:

GENERAL: I ascended at sunrise this morning. The enemy's line of pickets in front of this point (Doctor Gaines" house) remains, as usual, from one-half to