Instantly he stiffened. Every muscle became as taut as tempered steel.

He scarcely seemed to breathe while his unwinking eyes tried to bore through the ma.s.s of tangled brush and wire to see what was on the other side.

There too the rustling sound had ceased and a silence prevailed as deep as his own.

For minutes that seemed ages this condition persisted. Then slowly, so slowly that Frank at first was not sure that he saw aright, a slender spear-like point broke the outline of the top of the hedge. Only the fact that it stood out against the dim light that came from the enemy trench enabled Frank to see it at all.

Gradually the object rose higher until it seemed to broaden out at the base; and then with a quickening of the pulse Frank realized that what he saw was the spike of a German helmet!

He had won in the duel of silence. The other, unable to stand the strain, had risen first. Would he win in the grimmer duel that seemed to be impending?

Frank's fingers stole toward his revolver, but stopped before they reached it. There must be no shooting so near the enemy trench. A horde of Germans would be upon him in a twinkling.

His rifle lay beside him where he had placed it while working on the wire. His fingers closed upon the stock. Here was a weapon that he might use at either end with deadly effect. The b.u.t.t could serve as a club, while the bayonet, painted black like the rest of his accoutrements so that no glimmer of steel should betray it, carried death on its point.

Now beneath the helmet the head of a man appeared, then the shoulders, and finally the sentry, evidently satisfied that his suspicion had been without foundation, straightened out to his full length. He stood for another minute or two peering into the darkness. But Frank's black-clad form merged so perfectly into its surroundings and he remained so motionless that the German at last was convinced.

With a grunt of satisfaction he stooped to pick up his rifle.

Lithe as a panther, Frank sprang to his feet, leaped over the hedge and landed heavily on the stooping form, knocking the breath out of the German's body.

In a flash Frank's sinewy hands were upon the sentry's throat, stifling the cry that sought to issue from his lips.

There was a brief struggle, but the attack had been so sudden and tremendous that it was soon over, and the German lay limp and unconscious.

The instant Frank realized this, he relaxed his hold. He tore open the man's coat, felt for his heart and found that it was still beating.

What his foe would have done if the case had been reversed, Frank knew perfectly well. A dagger point would have pierced his heart and stilled its beating forever. More than once he had looked on the bodies of comrades who had been butchered while lying wounded and helpless on the battlefield, and had been stirred by a wild desire to take similar vengeance on those who had violated all the laws of war.

But he was an American, with all the proud traditions of honor and chivalry that had come down to him through generations. He could not slaughter a helpless foe. He had the man a prisoner. It was enough.

Quickly he tied the sentry's hands, using the German's own belt as a strap. Then he tore some strips from the white cloth he had been carrying to fasten on the bushes and made a gag, in case the man should recover his senses and try to give the alarm.

He dragged the man through a gap in the hedge so that he would not be found by any of his comrades who might come that way. Then he crept down to where the corporal and the other members of the patrol were still busy on the wires and in a whisper told what had happened.

Wilson was quick to see the opportunity that the capture had afforded.

"Good work, Sheldon," he commended. "Here's where we get through the wires. And we've got to do it quickly, for we don't know at what time that fellow's relief may be coming along."

His prophecy seemed about to be fulfilled with startling suddenness, for, even while he spoke, a group of several figures, topped by helmets, was revealed by the action of one of them in striking a match. It flared up brightly for a second, but luckily the boys were outside the zone of light that it formed.

They lay perfectly still, although each of them took a tighter grasp on his rifle.

The men conversed in guttural tones for several minutes, that seemed as many ages to the watchers in the shadows.

Would the Germans come toward them or walk away from them? Their lives, or at the least their liberty, might depend upon the answer.

One of the men pointed in their direction and even took a step forward, but his comrades stopped him and an animated discussion ensued, which finally resulted in their retracing their steps in the direction from which they had come.

A sigh of relief went up from the boys and their grip on their weapons relaxed.

"A mighty close shave," whispered Billy.

"It was all of that," agreed Bart.

"As close for them as it was for us," said Tom grimly. "I had that big fellow picked out and I'd have dropped him sure."

Like so many ghosts, the party drifted along in Corporal Wilson's wake until they came to the gap. A glance at the motionless sentry showed that he had not yet returned to consciousness.

"That was a knockout for fair," murmured Billy admiringly.

"He must have thought a house was falling on him," whispered Bart with a low chuckle.

"Frank's no featherweight," agreed Tom. "I'd hate to have those trench clogs of his come down on my back with him inside of them."

A warning "s--sh" from the corporal brought them back to the grim business still before them, and they crept along behind him as he wormed his way through the breach.

Camp utensils were scattered upon the ground and indicated that a field kitchen had stood there recently, an impression that became a conviction when Bart burned his hand by bringing it down upon some smoldering embers covered with ashes.

He bit his tongue trying to repress the exclamation that leaped to his lips, but he succeeded, although his fingers were badly blistered.

Little by little, with many pauses, they reached the edge of a small section of the first trench. Nothing hindered them, no one challenged them. In fact their progress was so free from obstacles that the corporal, a wily veteran who had had long experience among the savage Moros while serving in the Philippines, became uneasy, fearing an ambush.

Still, that was one of the chances that the party had to take, and there was nothing to do but to keep on. But they redoubled their precautions, every sense tingling with watchfulness against a sudden surprise.

They worked their way along the trench until they reached the entrance.

No sound came from the interior. They listened for the murmur of conversation, the sc.r.a.ping of feet, the clank of a weapon. They looked down its length for a ray of light. Not a gleam or a sound rewarded them.

As far as they could judge, it was absolutely deserted. But on the other hand it might be bristling with armed men, waiting in a stillness as deathlike as their own the command to fire.

For fully ten minutes their watch continued. Then the corporal gathered them close around him and gave his commands in a whisper.

"We'll raid it," he decided. "There are only a few of us, but we'll have the advantage of surprise. That is, if they're not waiting to surprise us. But we'll have to gamble on that. It's only a connecting trench, and there won't be more than a dozen men or thereabouts in it. If we could bag them and take them back to camp it would be a good night's work.

Have your guns ready and be prepared to slip them a few grenades if we have to. I'll lead the way and when the time comes I'll flash my light.

Come along now and be right on your toes when I give the word."

Corporal Wilson went first and his scouting party followed close on his heels. It was like going into the jaws of death. It would have taken less nerve to face a charge, for then their blood would have been up and they would have been fired by the sight of their enemy. There would have been nothing of this eerie stillness, this vault-like chill. Yet not one of them hesitated or lagged behind.

Twenty paces had been covered when the corporal stopped, drew out his flashlight and sent out a stream of radiance that illumined every nook and cranny of the trench.

On the instant the boys had their rifles at their shoulders with their fingers on the triggers, ready for a volley.

But their precaution was needless. The trench was empty!

Empty as far as men were concerned. But it was full of other things that made their hair stand up with horror as their meaning swept in upon them!