I looked and found on March 25, 1862 at Island No. 10....
March 25.--At about 3 p. m. balloon ascensions were made in Captain Steiner's balloon Eagle, to the height of 500 feet. The day being hazy they could not define fully the position of the enemy, but the experiment proved satisfactory. Second Masters G. B. Simonds and E. W. Wheelock report having fired, respectively, from No. 23, 17 and from No. 38, 13 shell.
I also found references to Eben Seaver being assigned to take the Eagle to the Mississippi River to assist in the war there.
More balloons on the Mississippi were Confederate signal balloons...
"While lying at Dead Man's Bend, on board the General Bragg, I discovered what was to me a new manner of making night signals, used by the rebel signal corps. Being well calculated to deceive even a most experienced eye, I regard them to be eminently dangerous. While standing upon the deck of the Bragg one clear evening, I observed a light suddenly shoot up into the sky from a mass of timber to a height of about 200 or 300 feet or thereabouts and then become stationary for a few moments. (This was opposite Jackson's Point.) The light then presented the appearance of a fixed star of first or second magnitude. To a casual observer it would have seemed to have been a bright star. Being attracted by its peculiar manner of ascent, I watched it closely with a powerful glass, and soon solved the apparent mystery. It was a small balloon, to which was suspended a lantern, and was retained in its position by a cord extending to the earth. After being held stationary for a moment or two, it was danced up and down several times. Immediately a similar light shot up from the trees on the opposite side of the river, about 1 mile from Jackson's house, then another in the vicinty of Black Hawk Point, and then another on the opposite side of the river. Captain Dominy, commanding the General Bragg, immediately commenced shelling the woods where the second light appeared, when the whole of them were suddenly drawn down. I saw similar signal lights on several occasions afterwards, some of which were white, some pale yellow, and some pale red. I notified all the commanders in the vicinity of the fact, and they are now on the qui vive. From the feeble description I have been able to give you of these signal lights, you will readily perceive how rapidly information of the movements of our vessels and troops, etc., may be conveyed. They are particularly mischievous between the head of Glasscock Island and just below Bayou Sara."