He knew by its lack of weight that it was empty, and he laid it aside.

Then he paused for a glance at the sentinel who was still walking steadily on his beat, and whom he now saw very clearly.
He was disappointed to find the first canteen empty, but he was convinced that some in that heap must contain water, and he would persevere.

The second and third failed him in like manner, but he would yet persevere.

The fourth was heavy, and when he shook it gently he heard the water plash.

That thirst at once became burning and uncontrollable.