Thanks Bob, I found his unit, the 2nd Massachusetts Infantry, they were at the first Battle of Winchester, Va, May 25th, 1862. After his return to his unit he was detailed on extra duty as a Draughtsman at Head Quarters Defense of Washington. He was discharged Jan 23, 1863 by having received a civil appointment in the Engineers Dept. Looks like he was a good artist also. When he was in the 2nd Mass Inf his name was spelled Davignon.