"I'm no sleuth, but it looks to me as if Uncle Barney went into the woods and two persons followed him!" exclaimed Jack.

"Just the way it looks to me, too," answered Fred.

"Let's go and follow up those footprints at once," suggested Andy.

The others were willing, and in a short s.p.a.ce of time they were on their snowshoes and making their way through the woods in the center of the island.

"h.e.l.lo! here's something!" cried Jack presently, and pointed to the old lumberman's snowshoes, where they still rested among the branches of a tree.

Then the boys saw where he had climbed between the rocks, and, taking off their snowshoes, they followed the footprints.

"A cave!"

"What do you know about that!"

It did not take the lads long to reach the entrance of the cavern. Then Jack, who had brought along one of the flashlights, turned it on and entered, followed by his cousins.

"h.e.l.lo, Uncle Barney!" he cried out at the top of his lungs. "Uncle Barney! are you here?"

"Help! help!" came feebly from the inner end of the cave, and, guided by the flashlight, the four Rovers ran in that direction. They found the old man sitting on a rock with his head resting on his arm.

"Are you hurt? How did it happen?" questioned Jack quickly.

"They've robbed me!" moaned the old lumberman. "They came up behind me, and somebody hit me in the head with a rock! Then they ran away with my tin box!"

"Who was it? Are you badly hurt?" questioned Randy.

"I guess I'm not so awfully bad off, even though my head did bleed some," answered Uncle Barney. "But the worst of it is, they got away with my tin box--the one that's got the deeds to this island in it, and all my other valuables, including my dead wife's jewelry and a thousand dollars in gold."

By this time the boys were examining the old man's head. They saw where the rock had struck him, making quite a cut, from which the blood had flowed over one ear. It was much swollen, and over it Uncle Barney had tied a bandanna handkerchief.

"I'll get some snow and wash it off with that!" cried Fred, and did so.

Then the wound was bound up once more, and Uncle Barney said he felt better. He told his story in detail.

"What am I going to do?" he groaned. "Those rascals have got my treasure box!"

"Who were they?" questioned Randy.

"I don't know exactly. I heard them talk, and faced them with my gun.

They were in the dark, so I couldn't distinguish them very good. Then one of them threw a big rock, and that is all I can remember. As soon as I became unconscious they must have grabbed the box and run away with it."

"It must have been either Asa Lemm and Mr. Brown, or else Slugger and Nappy," said Randy.

"I don't know what I'm going to do, now those deeds are gone--not to say anything about my wife's jewelry and all that gold!" groaned the old lumberman.

"Just you take it easy, Uncle Barney. You mustn't excite yourself now,"

said Jack kindly. "We'll do what we can toward getting the box back."

The boys had brought some food along, and they insisted upon it that the old man eat and drink something. This seemed to strengthen Uncle Barney greatly, and he arose to his feet.

"Now we'll get after those rascals," he said, with something of the old-time fire in his eyes. "I'm not going to allow 'em to rob me in this fashion!"

While the old lumberman had been eating, the Rover boys had glanced around the cave curiously. It was a place partly natural and partly artificial. On one side it looked as if a little mining had been done, and Jack, who had studied geology, gazed at the surface of rocks and dirt with much interest.

"Why, Uncle Barney, this looks to me as if it was zinc ore!" he cried presently.

"Hush, hush, boy! I don't want anybody to know about that!" answered the old man quickly.

"Then it is zinc ore, is it?" queried Randy, who had also been inspecting a side of the cave.

"Yes, if you must know," was the surprising reply. "Right here, in the middle of this island, is one of the most valuable zinc ore beds to be found anywhere."

CHAPTER XXIX

THE DISCOVERY

"The trouble is, those rascals have a twenty-four hours' start of us,"

remarked Jack. "For all we know they may be miles away by this time."

"It's too bad Uncle Barney didn't take our advice and either have those deeds recorded, or else place them in some bank vault," said Fred.

"The thing now is to see if we can trail those fellows, whoever they were," put in Randy.

"That's the talk!" cried his twin. "No use of crying over spilt milk, as the cat said when she tipped the pan over into the well," and at this remark there was a faint smile.

The Rovers had drawn to one side to talk over the situation while Barney Stevenson was preparing to accompany them from the cave. The old man was both excited and worried. He cared little about the wound he had received on the head. All he wanted to do was to get back his treasure box, as he called it.

The little party soon reached the point where all had left their snowshoes. They looked around with care, and presently made out a trail leading toward the lake sh.o.r.e.

"If they went down to the lake, they most likely skated away," remarked Fred.

It was an easy matter to follow the trail through the snow. It led up to the vicinity of some rough rocks, and here turned southward.

"I guess they reasoned that they couldn't get over those rocks,"

remarked Uncle Barney. "Maybe they were afraid of a bad tumble. I wish they had gone over them and broken their necks!" he added bitterly.

"If only they had dropped the treasure box in the snow!" murmured Fred.

"No such luck for us, Fred," responded Jack. "I'm afraid that box and its precious contents are far away by this time."

They continued to follow the footprints, and at the end of a quarter of an hour found themselves at something of a clearing between the trees.

Here those who had stolen the box had evidently stopped to rest, for it could be seen where they had been seated on a fallen log, and where they had placed the box.

"Look here!" cried Jack, who was inspecting the ground closely. "Just as I thought--those fellows were Slugger and Nappy, I feel certain." He pointed to several half-burnt matches, and also a number of cigarette stubs.