were startled to observe a circle of light appear upon the stone floor of the apartment at some little distance from the spot where they were standing. It appeared to emanate from an electric searchlight held in the hands of the stranger.

Ned took a step toward the light. Jack and Harry did likewise. Their surprise increased as they observed that the light moved along the floor at a pace about equal to their own.

Ned thought that he could faintly discern the feet of the person carrying the light, but was unable to learn anything of the character of the person. He was torn between his desire to escape from the apartment and the wish to learn the identity of the stranger.

Only a few steps had been taken by the stranger before the light was extinguished. Instantly the three boys halted.

"S-s-sh!" came a warning hiss. "Be mighty careful now of your conversation and your footsteps. Keep as quiet as possible and follow me closely. We are all in extreme danger!"

In spite of his efforts at self-control, Ned's muscles trembled and he found it difficult to walk steadily. Assuming that his chums were in like plight, the lad summoned all his courage and reached out a reassuring hand to the others. The contact with his friends seemed to restore the equilibrium that had been Ned's most valuable asset in times of stress and danger in his many adventures.

Long afterwards the boy declared that in all his experiences that compassed many strange and hazardous enterprises in the United States, Canada, Mexico, the Philippines, China and other countries he had never felt so keenly the need of aid as he did at that moment.

Not for long, however, were the boys permitted to consider the peril of their position. Almost instantly they heard a faint grating sound directly in front of them. A cold draught of damp, musty air struck their faces, and they understood that a door had been opened into some other apartment. The odor of the incoming air told them plainly that the next apartment was also underground, and they surmised that it had not recently been occupied.

"Come!" was the command borne to their ears in the faintest of whispers from the person leading the way.

Unhesitatingly the lads advanced. Jack had taken but a couple of steps before he collided with some solid object. The shock of contact brought forth a grunt of surprise. At the same moment Harry went through a similar experience. Ned met no resistance and nearly lost his hold of the others before he recovered his balance.

"Gee!" Jack whispered, "I've hit a wall!"

"Here, too!" put in Harry, lowering his whisper to a mere breath.

"Single file, lock step," directed Ned.

Jack and Harry fell in behind their Scout Master obediently, and the little party began groping its way along. Ned reached out a hand on either side as he went forward. His hands came in contact with walls that appeared to be made of stone. The dampness had gathered in great drops on the surface. A slime had been deposited that made Ned shudder as he felt it. He knew, however, that this was no time to permit an interruption through squeamishness.

There was now no guiding light in advance, and the boys cautiously picked their way along the stones, with Ned feeling every inch of the way before he set his foot down. Directly the lad heard another warning hiss. This time the sound was closer than formerly.

"Put your hand on my shoulder," came the whispered command.

Ned followed this instruction immediately. He judged by the height to which he raised his hand to rest it upon the other's shoulder that the stranger was a person of about his own build. His sense of touch also told him that the other's clothing was of a material similar to the khaki uniform he himself was wearing. A faint odor of gasoline and grease assailed his nostrils, particularly distinguishable because of the damp air in which the party was traveling.

Suddenly the boys were startled by the sound of an explosion that came faintly to their ears. The earth in their vicinity trembled.

"What's that?" asked Ned in a whisper. "What's going on?"

"Hush!" replied the guide. "The Germans are making some improvements in the town. They are blowing down some dangerous walls. Now keep as quiet as you can and follow me. We'll have to hurry!"

Ned made no further attempt at conversation, but obediently gave his entire attention to following the strange person in advance.

Before the little party had traversed the passage to any considerable distance they heard several other explosions similar to the first. One particularly louder than the others was followed by the sound of small pieces of rock tumbling from the roof and walls of the passage. Ned pressed still closer to his guide, while Jack and Harry needed no urging to make them crowd up to Ned in their impatience.

Not far from the point where the boys had noticed the pieces of rock falling the guide turned a corner abruptly. Ned wondered how he was able in the intense blackness to distinguish so accurately the spot for making the turn, but refrained from making any comment.

As he followed the guide around the corner the lad's foot struck against an object lying on the floor. A metallic ring from the object he had kicked caught the lad's attention. Slipping his hand quickly down the other's back in preparation for a movement to pick up the object, Ned was surprised to come in contact with a belt. He was startled to observe that the belt was filled with cartridges.

Without stopping to comment upon the circumstance, Ned stooped quickly with hand outstretched. His fingers came in contact with the object his foot had struck. He instantly recognized it to be an automatic pistol. Restraining his impulse to cry out, the lad shifted the weapon in his hand to a grip that would permit him to use it in case such a move was necessary. He straightened up at once.

Scarcely had the boys taken another dozen steps before they heard the voices of a number of men, all apparently endeavoring to talk at once and using a language that was unintelligible to the lads.

Greater caution, if possible, was now used by all in their negotiating the dark passage. A few steps farther on carried them past the place where the voices had been heard. Ned breathed a sigh of relief as the voices died away in the distance.

Presently the guide halted. He turned to a position where he could face Ned. Still speaking in a whisper, he said:

"We are not out of danger yet, but I'll thank you to let me have that automatic you picked up back there. It's mine!"

"Come on, now, hand it over," continued the other.

"Where did you get it?" whispered Ned. "Can you prove what you say?"

"Of course I can!" replied the other. "I'm a bird man, and that is part of my equipment. You have no right to it!"

A louder detonation than any they had heard yet drowned Ned's reply. The walls in the passage seemed shaking as if about to fall. From the passage in their rear came shrieks and groans. An odor of sulphur came blowing upon their backs. A crashing and grinding noise filled the air. Jack and Harry closed in upon the others.

"Let's get out of here as quick as we can," urged Ned.

"We're at the end of the passage!" declared the guide. "That blast has probably filled the corridor back of us with rubbish. Unless we can dig a way out of it, we're buried alive!"

CHAPTER V.

A GUARD IN DISGRACE

Jimmie's momentum carried him toward the camp kettle with such violence that he was unable to check his speed. He could only swerve his course enough to avoid actually falling into the open door through which fuel had been fed. Unfortunately, however, the lad lost his footing and, as he fell, thrust a hand against the hot iron.

"Ow, wow!" yelled Jimmie, as he rolled over the ground, dragging with him the already burning Cossack uniform.

"Here, here!"