For what purpose does Brooks begin Chapter Four with March’s 1862 letter to his wife?

March writes to his wife from outside Hayden's Ferry, where he details the soldiers' questioning of faith. They are growing desperate and the weather is atrocious. This section is integral to showing the reader that there was sin on both sides of the Civil War. Popular American history remembers all Union soldiers as heroes and all Confederate soldiers as demons. In reality, many Northerners hated slaves as much as Southerners and particularly feared that once freed, the slaves would come up North and steal their jobs. This section discusses that fear and also presents a scene of Union soldiers brutally attacking a defenseless Southern woman and child just for fun. The colonel refusing to dole out punishment illustrates how corruption affected the entire rank of the Union army - as well as the Confederate - not just the uneducated farm boys turned soldiers.