What does the water symbolically represent?

In "A Mystery of Heroism" the bucket of water is a very important symbol in two respects. Firstly, it represents heroism. Fred Collins shows extraordinary courage in going off to fetch the bucket of water in the heat of battle. The fighting is intense; Fred could be cut down by a bullet at any moment. Yet his thirst is so great that he's prepared to risk life and limb to go get something to drink.
At the same time, the bucket symbolizes the utter futility of war. Fred's heroics are ultimately in vain; soon after he returns from his courageous mission, the bucket lies empty on the ground. Using the symbol of the bucket of water in such completely different ways allows Crane to express his hostility toward war, while at the same time paying fulsome tribute to the immense bravery of those who serve and fight.