The data was stark. Of twenty-nine regiments surveyed, ten reported that at least a third of their number had simply collapsed from exhaustion before the battle even started. For many of these soldiers, the cause of such breakdown was want of water, food, or sleep. Others had been worn out by the need to march the final miles to battle at a punishing pace known as “double-quick.” Combining the march and the retreat, Olmsted determined that the average soldier traveled forty-four miles on foot the day of the battle.
