[Indorsement.]

HEADQUARTERS ARMY OF THE POTOMAC,
March 20, 1863.

Respectfully returned.

It was inferred the tests made proved the expediency and capacity of the plan. Has not Professor Lowe balloons and signals enough on hand of the kind proposed to show their merits for this purpose? If he has, a board will be ordered immediately to report upon them. Return these papers without delay.

By command of Major-General Hooker:

S. WILLIAMS,

Assistant Adjutant-General.

HEADQUARTERS AERONAUTIC CORPS,
Camp near Falmouth, Va., March 21, 1863.

Brigadier General S. WILLIAMS,

Assistant Adjutant-General, Army of the Potomac:

GENERAL: In answer to your indorsement upon my communication of yesterday, I would respectfully say that I have not on hand any signal balloons of the size or quality sufficient to show the merit, or to carry up sufficient weight of material for which they are designed.

I have some few balloons left of those ordered by Major-General Burnside, for experiments, but were gotten up in a hurry, and made of very poor material, but the best that could be obtained at the time. They will do very well to use for instruction. I have on hand a quantity of colored fires, but will require to be arranged differently, with some addition, in order to give the full effect and brilliancy desired. I have not any of the proper material on hand for the flags. My extreme estimate of the expense of these experiments was based upon the supposition that a large number of the signals would require to be sent up, embracing every variety of lights, flags, and characters upon the balloons, in order to choose the most desirable.

I am, general, with great respect, your most obedient servant,

T. S. C. LOWE,

Chief of Aeronautics, Army of the Potomac.

[Indorsement.]

HEADQUARTERS ARMY OF THE POTOMAC,
March 21, 1863.

Respectfully returned.

Under the circumstances not favorably considered. General Stoneman to be informed by Professor Lowe.

By command of Major-General Hooker:

S. WILLIAMS,

Assistant Adjutant-General.

By the decision in this matter General Stoneman was deprived of a very valuable means of communicating with the commanding general while operating in the interior of the enemy's country. With the signal balloons alluded to General Stoneman could have been heard from every night, and answered from Fredericksburg, which certainly in his last famous raid would have been of great value both to him and to General Hooker.

These intense lights by the aid of balloons, varying in size from ten to twenty feet in diameter, can be sent from 3,000 feet to three miles in the air, and can be seen from 15 to 100 miles, according to the size of the lights. At any rate I would not hesitate on any clear night (with the proper facilities) to guarantee to signal even to a greater distance.

HEADQUARTERS ARMY OF THE POTOMAC,
March 21, 1863.

Prof. T. S. C. LOWE, &c.:

By direction of the General-in-Chief, you will report on Monday morning next to the Committee of Congress on the Conduct of the War, now sitting in the Capitol.

By command of Major-General Hooker:

S. WILLIAMS,

Assistant Adjutant-General.