 Complete the following phrase:  Early in the war Burnham became lieutet colonel of the 6th Maine Infantry on July 16, 1861. He was promoted to the rank of colonel on December 12 of that year. He served with the Army of the Potomac in the Peninsula Campaign, starting out in Brig. Gen. Winfield S. Hancocks brigade in a division of the IV Corps under Brig. Gen. William F. Smith. This division later became part of the VI Corps. At the Battle of Cramptons Gap and the 