This fine wearther will not last long. Please have the aeronaut improve every opportunity.

T. S. C. LOWE,

Chief Aeronaut.

WASHINGTON, December 1, 1861.

WILLIAM PAULLIN,

In Charge of Balloon, Budd's Ferry:

Do not reinflame the balloon until it has another coast of varnish, unless it is perfectly tight. I will send you an assistant all the necessary articles to-morrow. Improve every calm from daybreak until dark. Examine the shore opposite Mattawoman Creek, and keep me constantly informed.

T. S. C. LOWE.

WASHINGTON, D. C., December 3, 1861.

Lieutenant Colonel A. V. COLBURN,

Assistant Adjutant-General:

DEAR SIR: I have the honor to communicate to you the disposition thus far of the new balloons is my charge. The balloon Constitution is at Budd's Ferry-General Hooker's division. The Washington, with gas generating apparatus and materials, is en route for Port Royal S. C. The Intrepid, of larger dimensions, is at General Porter's division, Hall's Hill. The Union, same size, is intended for Poolesville, and is now ready, but has been delayed at the navy-yard for work on gas- generating apparatus that was promised me three weeks ago. It was supposed to be a matter of economy to have this apparatus constructed at the navy-yard. This season of the year is not the most propitious for continued reconnaissances, but when all the work now under my supervision is completed, no favorable opportunity for observations, night or day, will be allowed to pass unimproved.

I have thus far exercised, and in the future shall continue to exercise, the most untiring diligence in the prosecution of the important labors intrusted to me; but, in my judgment, the interests of this branch of service require the immediate construction of two small balloons, for the following, among other reasons, which I herewith respectfully commend to your favorable consideration: When General McClellan recommended, and the Secretary of War ordered, the addition of four balloons, the possibility or probability of using either of them at the South was not considered; therefore, as the ample supply of coal gas at Washington justified me in doing, I made two of them of larger dimensions, so that being filled with coal gas they would economically accomplish the equivalent of the work expected from a smaller envelope filled with hydrogen, notwithstanding the difference in levity of the two gases. These two small hydrogen balloons, as compared with the larger ones, will be particularly serviceable at the present time, as they will require one wagon less each for moving generators, while the diminished amount of material required will also tax our transportation facilities to a much less extent.

Lastly, the most important advantage gained will be that a light balloon, of small dimensions, well filled with hydrogen, presents so much less surface to the wind, and can consequently be used in the heavier wearther. These qualities are embraced in the balloons Washington and Constitution.

Hoping the general will allow me to construct the two small balloons, while the larger ones are held in reserve as future contingencies may determine,

I remain, dear sir, very respectfully, LOWE.

WASHINGTON, D. C., December 10, 1861.

Lieutenant Colonel A. V. COLBURN,

Assistant Adjutant-General:

DEAR SIR: One of my assistants arrived this morning from General Hooker's headquarters and reports that the balloon has been constantly used for the past week making observations of the enemy's movement and position. A large number of ascension have been made, the aeronaut being accompanied by Colonel Cowdin, Colonel Small, and others. Colonel Small while up with the balloon made a very fine map of the enemy's works and surrounding country, a copy of which is being prepared, and will be forwarded to headquarters.

Very respectfully, your obedient servant,

T. S. C. LOWE,

Chief Aeronaut.