"What are you prowling about the yard for?"

The detective dropped to his knees and began crawling away.

"If I see you around here again," the caretaker shouted in a braver tone now that the intruder was taking his departure, "I'll do some shooting!"

Evidently giving over the attempt to enter the mine at that time, the detective arose to his feet as soon as he gained the shelter of the weigh-house, and walked away, pa.s.sing as he did so, within a few feet of where the boys were standing.

"That settles that b.u.m detective, so far as we are concerned!" Will said to his chum, in a whisper. "We knew before that he was playing a rotten game on us, but we didn't know that his plans included such surrept.i.tious visits to the mine."

After making sure that the detective was not within sight or sound, Will and George tapped softly at the little door and were admitted by the caretaker. Five minutes later they were joined by Tommy and Sandy.

"Were you boys out there a few moments ago?" asked Canfield.

"Nix!" replied George. "That was Ventner. We saw him from the weigh-house. He was trying to sneak his way into the mine!"

"But he has full permission to enter at any time he sees fit!" urged the caretaker. "It doesn't seem as if he would attempt to steal his way in during the night. You must be mistaken!"

"Yes, and perhaps we were mistaken about the sawing of the ladder, too!"

Tommy broke in.

"Yes, we may all be mistaken about that."

"Not so you could notice it!" declared Sandy. "If you look at the thief's coat, you'll see that he didn't do all the sawing on the rungs of the ladder. We've got him too dead to skin!"

Without any lights being shown on the surface, the boys were conducted down the ladder to the first level. There they found a room very cosily furnished, indeed. A lounge from the office, a couple of good sized cupboards, and a large table had been brought down, together with a serviceable rug and numerous chairs, and the apartment presented an unexpectedly homelike appearance.

The current was on, and two electric lamps made the room as light as day. The cooking was to be done over electric coils so that the presence of the boys would not be disclosed by smoke. One of the ventilating pipes which supplied the offices in the vicinity of the shaft with fresh air pa.s.sed through the room, so there was no lack of ozone.

"Have we got plenty of eatings?" asked Tommy.

"Plenty!" was the reply. "I have arranged for fresh meat, milk and vegetables to be brought in every evening."

"Talk about your bull-headed, obstinate men!" exclaimed Tommy, as the caretaker finally took his departure. "That fellow takes the cake! He knows very well that we caught Ventner in the act of sawing on the ladder, and he knows, too, that we heard Wolf calls while we were in the mine. Still, he shakes his head and says that he don't know about the boys being there, and don't know about that b.u.m detective being crooked.

If you could get a saw and operate on his head, you'd find it solid bone!"

"You'll feel better after you get supper!" Sandy declared.

"This isn't any grouch!" insisted Tommy. "This is the true story of that man's life! If I had a dollar for every time he doesn't know anything, I'd be the richest boy in the world!"

"Are you thinking of going down the mine tonight?" asked George, with a wink at Will. "We might try another midnight excursion."

"If you kids go into the mine tonight," declared Will, "I'll send you both back to Chicago on the first train!"

"Aw, how are you going to find these boys if you don't go into the mine?" demanded Tommy. "I suppose you'll want us to wait till daylight when the owners will be looking around to see if any damage was done by the inundation. The best time is at night!"

"Look here," Will argued, "we've got to do more than lay hands on the boys! We've got to find out why they are hiding in the mine."

"That's the correct word," agreed George. "Hiding is the word that expresses the situation exactly!"

"There is no doubt," Will continued, "that the boys were sent here by some one for some specific purpose. They are hiding in the mine with a well-defined motive. I have an idea that we might be able to find them in twenty-four hours, but what is more important, is to find out what they are up to."

"Well, in order to get the whole story, we'll have to pretend that we are looking for them and can't find them!" George said.

"That's right!" laughed Tommy. "Give them plenty of rope and they'll hang themselves. We may as well have the whole story while we're at it."

Before preparing their beds for the night, the boys paid a visit to the shaft and made their way down to the rungs which had been cut. They found that they had been replaced by new ones.

There was still water in the lower levels of the mine, but it was slowly disappearing through the sump, and the indications were that it would be dry by morning. The boys listened intently for some evidence of occupancy as they moved up and down the shaft, but all was still.

"This would be a good place to tell a ghost story," Tommy chuckled as they moved back to their room on the first level.

"There's about a million stories now, ent.i.tled The Ghost of the Mine!"

declared Sandy. "Perhaps however," he went on, "one more wouldn't hurt."

"If I see a ghost tonight," declared Tommy, "it'll be in my dreams!"

Sandy and Tommy were sound asleep on their cots as soon as supper was over, and Will and George were getting ready to retire when the soft patter of a light footstep sounded in the vicinity of the shaft.

"Rats must be thick in the mine!" suggested George.

"Rats nothing!" declared Will. "Those two youngsters are prowling about in order to see what we are up to!"

As he spoke the boy arose, turned off the electric light and stepped out into the pa.s.sage.

CHAPTER XII

A MIDNIGHT ROBBER

There was a quick scamper of feet as Will stepped out, then silence!

"Where did he go?" asked George, joining his chum on the outside.

"Down the ladder!" replied Will.

"Why don't we go and see where he went?"

"That might be a good idea," Will replied. "Do you think it's safe for us to try to navigate that shaft in the dark?"

"We can stick to the ladders, can't we?" asked George.

"We ought to find out where the kids hang out," Will argued. "I'd like to get my hands on one of them!"

"I don't think we're likely to do that tonight," George answered. "It seems to me that about the only way we can catch those fellows is to set a bear trap. They seem to be rather slippery."

Will, clad only in pajamas and slippers, moved toward the shaft, and looked down. It was dark and still below, and he turned back with a little shudder. The situation was not at all to his liking.