He was up in a moment, however, and, picking up his sword, was soon in the saddle again; and a moment later the mules again were being crowded off the road.

The German was within striking distance, but Hal had nothing with which to hit him.  His other empty revolvers had already been thrown.

“Hit him with the whip!” he cried to Chester.  “Hit him with the whip!”

Chester, suiting the action to the word, simply diverted one of the blows intended for the mules, and struck the German fair across the face.

The whip had a knot on the end of it, to keep it from unraveling, and this knot hit the German in the eye.  The German dropped his sword, put his hands to his face, and rubbed his eyes; then, putting spurs to his horse, he made off rapidly over the road which they had come.

The boys now caught the first glimpse of the town of Louvain, and the glad sight of Belgian troops could be discerned—­the outposts guarding the town.

Chester let the mules slow down.

“That was some ride,” he declared.

“You bet,” was Hal’s answer.  “I thought we were gone that time, sure.”

“Well, let’s get out and walk the rest of the way,” said Chester.  “I have had enough of this riding to last me a lifetime.  The wagon jolted so much I must be black and blue all over.”

Chester stopped the mules, and the boys climbed to the ground; and, just as they started to resume their walk, Hal sank suddenly to the ground!

CHAPTER XXI.

Through walls of fire.

Quickly Chester bent over his friend.

“Hal!  Hal!” he cried in alarm, shaking him gently.  “Tell me where you are hurt!”

He laid his friend’s body back gently; then for the first time he noticed that blood flowed from a wound in Hal’s side.

In vain did Chester try to bring his chum back to consciousness.  The boy lay like one dead.  Finally, seeing that his efforts to revive his companion were useless, Chester picked him up in his arms, and in this manner started for the town.

By pure grit Chester succeeded in carrying his burden to the Belgian outposts, where he turned him over to a Red Cross surgeon.

“Is he badly hurt?” the boy demanded, as the surgeon arose from examining his chum’s wound.  “Will he live?”

“It is dangerous,” was the reply.  “But I think he will come around all right presently.  But he has had a narrow escape.  One inch higher up and the bullet would have pierced his heart.  He must be taken to the hospital.  He must have proper attention.”

Leaving his chum in good hands, Chester made his way to General Givet’s tent, where he gave him the message the boys had gone through so much to deliver safely.  Then he went to the hospital.  He was permitted to see his friend at once.

Deathly pale, but with a smile on his face, Hal greeted his friend.  Chester sprang forward and grasped his hand.