Comparing these two deaths is an interesting writing prompt, as it would likely be better to contrast the two deaths.
Sullivan Ballou was a Rhode Island lawyer and politician. During the Civil War, Ballou was an officer in the Union Army, and he died as a result of the wounds received in the First Battle of Bull Run. He took a cannonball to the leg, and the remainder of the leg had to be amputated. Ballou died five days later on July 26, 1861 in a battlefield hospital at Sudley Church, Virginia. Similarly, Peyton Farquhar died during the Civil War. Both men died at similar ages. Farquhar was thirty-five years old at the time that the story takes place, and Ballou was killed at the age of thirty-two. Both men died at the hands of the enemy rather than dying of natural causes.
That is about where the similarities end. Ballou was a soldier fighting for the Union and the Confederates killed him. Farquhar, in contrast, was not a soldier. He was a civilian who supported the Confederate cause, and he was killed by Union soldiers. Ballou was wounded in combat and died as a result of combat. Farquhar had never seen combat and was executed for his attempt to sabotage a Union bridge.