That was good old Warren P Edgarton, later commander of the 1st Ohio Battery E and captured at Stones River! He wound up wearing a pair of high boots that were several sizes too small that he squeezed into for the speech, and a random assortment of military and civilian clothes. Quite the sight to behold when reading from the Declaration of Independence on the 4th of July!
If I recall correctly, according to the memoirs of the battery in addition to having poor uniforms at Marietta, it was also blazingly hot & muggy that summer they were in training. So the three months men tried to wear as little as possible... if I recall correctly one man was down to a shirt & drawers! Quite scandalizing for the ladies of Marietta, who hung around the camp helping make powder bags for the guns, ostensibly.
You've got to love the Mountain Howitzer. It didn't seem much service in the war, but it was a handy little piece that popped up in interesting places. It looks like there are four in the picture, enough to equip a battery of them. I for one really enjoyed firing the mountain howitzer last September. Maybe it was it's size, maybe it was better primers, or maybe I'm just getting more experienced, but the lanyard seemed much easier to pull and I don't recall any misfires that day... our battery is very fortunate to have not one but two mountain howitzers, both on the pack and the prairie carriages. They make a great little pair.