September 17 we received from General Burnside this:

Can you see any movements of the enemy on the road or elsewhere?

General BURNSIDE.

To General B.:

Yes; they are moving now a strong force of infantry from Shepherdstown into the woods west of Sharpsburg and northerly to our right.

Y. Y. Y.

Can you see any movement of the enemy, particularly in rear of the corn-field in front of us?

General BURNSIDE.

I can see no movement, particularly in rear of that corn-field

Y. Y. Y.

This last message, although insignificant now, was very important then, as it gave assurances that there was no immediate danger to be apprehended from that particular place. At 3 p. m. same day we sent:

To General BURNSIDE:

Look out well on your left; the enemy are moving a strong force in that direction.

Y. Y. Y.

This warning was in time, and it was noticed by General Burnside, as at that hour, I thing, General A. P. Hill arrived with his forces from Harper's Ferry to re-enforce the enemy.

These are all the messages I could preserve from that day, as then we had no tents on stations, no wagons, exposed for days and nights to constat rain, and consequently all papers, as everything else in our possession, must have been wet and destroyed.

From that time until the 28th ultimo I was posted on different signal stations, changing them almost every day, until we came to Rectortown, Va. From that place I was ordered to proceed with Lieutenant Owen to Thoroughfare Gap, and "open communication with Water Mountain, Warrenton" (9 miles distant, air line), and "observe the line of railroad." The highest point in that vicinity is on the Bull Run Mountain, called the "Leather Coat Hill," north of the gap, but unluckily the woods on the mountains north and south of that gap were set on fire, and it was impossible for any one to ascend the summit without being roasted. The other hills there are of so almost equal height that it was no easy task to find the proper one to answer our purpose; still, I have found such, as I had the honor to report at that time. We have not sent any reports from that station, because there was nothing to report then; yet that station was very important, and, I think, if it had been allowed to remain there longer, our troops would not have left the gap in such a great haste as they did.

A signal flag is a great annoyance to the enemy, as we have seen from their reports after the battle of Antietam, and also inspires our troops with confidence; when sen by them on some high point, or near them, they know that those near that flag are on the lookout, and look with better eyes than they have. As a proof of this, I will relate a circumstance from the battle at Gaines' Mill, on the Peninsula. When the battle raged in its greatest fury, a few pieces of artillery from General Smith's division opened fire across the Chickahominy upon the enemy. All saw the smoke, but not many could tell where the shells fell of who fired, as the pieces were hidden by woods from our view. Our soldiers began to murmur, "The rebels are outflanking us." All eyes turned in that direction, when a signal flax emerged from the woods and began