The ascension of the 24th of July, alluded to in the foregoing letter, was made in consequence of a report being circulated that the enemy was marching in force on Washington, which caused much excitement. The result of my observation, published the next day, showed this report to be untrue and restored confidence.

In this voyage I started soon after sunrise, while the atmosphere was clear, and sailed directly over the country occupied by the enemy, as the lower current was blowing toward the west. Having seen what I desired, I rose to the upper current and commenced moving toward the east again, until over the Potomac, when I commenced to descend, thinking that the under current would take me back far enough to land near Arlington House. When within a mile of the earth our troops commenced firing at the balloon, supposing it to belong to the rebels. I descended near enough to hear the whistling of the bullets and the shouts of the soldiers to 'show my colors." As I had, unfortunately, no national flag with me, and knowing that if I attempted to effect a landing there my balloon-and very likely myself-would be riddled, I concluded to sail on and to risk descending outside of our lines. This I accomplished, and landed on Macon's plantation, five miles and a half from Alexandria and two miles and a half outside of our pickets. A detailed account of my escape would be interesting, but it is sufficient to say that I was kindly assisted in returning by the Thirty-first Regiment New York Volunteers, and brought back the balloon, though somewhat damaged, owing to my having been obliged to land among trees. The balloon was generally supposed to be one of the enemy's, and the authorities in Washington were telegraphed from Arlington to this effect.

On the 29th of July I received the following dispatch from Captain Whipple:

ARLINGTON, July 29, 1861.

T. S. C. LOWE:

If you will at once repair your balloon, and will superintend its transportation to this side of the Potomac, the United States will employ you temporarily as follows: The United States will pay for the gas used for the inflation, will furnish twenty men to manage the balloon, will pay you $30 per day for each day the balloon is in use for reconnaissance on the Virginia side of the Potomac. The balloon to be ready for use within twenty-four hours.

A. W. WHIPPLE,

Captain, Topographical Engineers.

In answer to this I informed Captain Whipple that I could not enter upon such an arrangement, but that if the Government would direct me to construct a balloon such as I deemed suitable for military purposes I would only charge $10 a day for my services, instead of $30, and would guarantee entire success. I also stated the cost of the new apparatus and the time required for its construction.

I, however, repaired the balloon, as desired by Captain Whipple, but while transporting it with inexperienced men a distance of ten miles over a rough road, where there were many obstructions, we were overtaken by a heavy storm and I was obliged to discharge the gas. In relation to this occurrence I beg leave to refer to the following letter from Professor Henry:

SMITHSONIAN INSTITUTION, August 2, 1861.

Captain A. W. WHIPPLE,

U. S. Army:

DEAR SIR: I regret much to learn from Mr. Lowe that you think of giving up the balloon operations, and I write to express the hope that you will make further attempts. A single successful observation will fully repay all that you have yet expended.