“I reckon I had best stick to the tree and trust to luck to pass the rocks in safety,” he muttered, and clutched the tree with a firmer hold than ever.

The strange craft had now stopped circling, and was shooting straight ahead for a rock that stood several feet above water.  On it went, and Sam closed his eyes in expectancy of an awful shock which would pitch him headlong, he knew not to where.

But then came a swerve to the left, and the tree grated along the edge of the rock.  Before Sam could recover his breath, down it went over the first line of rapids.  Here it stuck fast for a moment, then turned over and went on, throwing Sam on the under side.

The boy’s feet struck bottom, and he bobbed up like a cork.  Again he clutched the tree, and on the two went a distance of ten feet further.  But now the tree became jammed between two other rocks, and there it stuck, with Sam clutching one end and the water rushing in, a torrent over the other.

For the moment the boy could do little but hold fast, but as his breath came back to him he climbed on top of the tree and took a look at the situation.

It was truly a dismaying one.  He was in the very center of the rapids, and the shore on either side of him was fifty to sixty feet away.

“How am I ever to get to the bank?” he asked himself.  “I can’t wade or swim, for the current is far too strong.  I’m in a pickle, and no mistake.  I wonder if Dick and Tom are on solid earth yet?”

He raised his voice into a shout, not once, but several times.  At first only the echoes answered him, but presently came a reply from a distance.

“Sam!  Sam!  Where are your?” It was Dick calling, and he was running along the bank alone, Tom being too exhausted to accompany him.

“Here I am —­ in the middle of the falls!”

“Where?”

“Out here —­ in the middle of the falls!”

“Great Caesar, Sam!  Can’t you wade ashore?”

“No; the current is so strong I am afraid to.”

In a minute more Dick reached a spot opposite to where the tree rested.  As he took in the situation his face clouded in perplexity.

“You are right —­ don’t try wading,” he, said.  “If you do, you’ll have your skull cracked open on the rocks.  I’ll have to get a rope and haul you off.”

“All right; but do hurry, for this tree may start on again at any instant!”

To procure a rope was no easy matter, for nothing of that sort was at hand, and the nearest farmhouse was some distance away.  Yet, without thinking twice, Dick set off for the farmhouse, arriving there inside of five minutes.

“I need a rope, quick, Mr. Darrel,” he said.  “My brother is in the middle of the Humpback Falls on a tree, and I want to save him.”

“Why, Dick Rover, you don’t tell me!” cried Joel Darrel, a farmer who had often worked for Randolph Rover.  “Sure I’ll get a wash line this minute!” and he ran for the kitchen shed.