At last their walking brought them out on the upper end of the island facing the smaller spot of land above.  As they emerged from the trees, both boys got a big surprise.

Two boats had just been beached there!

“What in the world!” stammered out Jack.

“Who can——­” began Tom, when the question was answered.  The boys saw three figures coming down to the beach.  They, seemingly, had been looking for a camp site.

“It’s that fellow, Bill Masterson,” explained Jack.

“So it is, and those other two are his cronies.  The sneaks, they’ve followed us here!” cried Tom indignantly.

“Let’s watch from behind these bushes and see what they do,” said Jack.

They watched from a place of concealment while the three youths on the island above unloaded the second boat which they had towed down the river, carrying their camping equipment and provisions in it.  They set up their tents quite boldly in full view of the other island and then proceeded to build a fire.

“How on earth did they get down the river without having a spill?” cried Jack.

“How did they know where Rattlesnake Island was?” wondered Tom, neither of the boys, of course, knowing of the opened letters.

“They seem prepared to make a long stay,” commented Tom, after a minute, “but it’s a wonder they weren’t wrecked.”

“I don’t know,” said Jack.  “Zeb says the river is much higher now than he has ever seen it.  That means that the rapids are not so dangerous as at low water.  But they were taking quite a chance, at that.”

The boys watched for a while longer and then returned to camp with their game and their news.

“If they try to land on this island, we’ll soon chase ’em off,” declared Dick vehemently.

“Then they’d have a case at law agin us,” said Zeb.

“How do you mean?” asked Jack.

“Wa’al, we ain’t filed no claim yet and in the eyes of the law them deposits down there in the black barren is as much theirs as ours.”

That evening Zeb occupied himself with making several signs of intention to file claim which he intended to post all round the black barren, thus marking it off as if it had been a mine.  Before they went to bed, Jack and Tom made another excursion to the upper end of the island where they watched the campfires of the interlopers for some time.

Suddenly, while they watched, they saw one of the boats with three figures in it shoved off.  The craft began to drop down the river.  Masterson, who was at the oars, steered straight for Rattlesnake Island.

“They’re going to land here,” declared Jack.

“What do you think of that for nerve,” gasped Tom.

“The worst of it is, we can’t stop them.”

“No, that’s so.  Let’s hide behind this rock and see what they do.”

The boys slipped behind a big boulder and a moment later the boat was beached.