He was the first awake the following morning, the first to take his place in the canoe.  Every minute now his ears were keenly attuned for that distant sound of falling water.  But hours passed without a sign of it.  Noon came.  They had traveled six hours and had covered twenty-five miles instead of fifteen!  Where was the waterfall?

There was a little more of anxiety in Wabigoon’s eyes when they resumed their journey after dinner.  Again and again Rod looked at his map, figuring out the distances as drawn by John Ball, the murdered Englishman.  Surely the second waterfall could not be far away now!  And still hour after hour passed, and mile after mile slipped behind them, until the three knew that they had gone fully thirty miles beyond where the cataract should have been, if the map was right.  Twilight was falling when they stopped for supper.  For the last hour Mukoki had spoken no word.  A feeling of gloom was on them all; without questioning, each knew what the fears of the others were.

Was it possible that, after all, they had not solved the secret of the mysterious map?

The more Rod thought of it the more his fears possessed him.  The two men who fought and died in the old cabin were on their way to civilization.  They were taking gold with them, gold which they meant to exchange for supplies.  Would they, at the same time, dare to have in their possession a map so closely defining their trail as the rude sketch on the bit of birch bark?  Was there not some strange key, known only to themselves, necessary to the understanding of that sketch?

Mukoki had taken his rifle and disappeared in the plain along the river, and for a long time after they had eaten their bear steak and drank their hot coffee Rod and Wabigoon sat talking in the glow of the camp-fire.  The old warrior had been gone for about an hour when suddenly there came the report of a gun from far down the stream, which was quickly followed by two others—­three in rapid succession.  After an interval of a few seconds there sounded two other shots.

“The signal!” cried Rod.  “Mukoki wants us!”

Wabigoon sprang to his feet and emptied the five shots of his magazine into the air.

“Listen!”

Hardly had the echoes died away when there came again the reports of Mukoki’s rifle.

Without another word the two boys hurried to the canoe, which had not been unloaded.

“He’s a couple of miles down-stream,” said Wabi, as they shoved off.  “I wonder what’s the matter?”

“I can make a pretty good guess,” replied Rod, his voice trembling with a new excitement.  “He has found the second waterfall!”

The thought gave fresh strength to their aching arms and the canoe sped swiftly down the stream.  Fifteen minutes later another shot signaled to them, this time not more than a quarter of a mile away, and Wabi responded to it with a loud shout.  Mukoki’s voice floated back in an answering halloo, but before the young hunters came within sight of their comrade another sound reached their ears,—­the muffled roar of a cataract!  Again and again the boys sent their shouts of joy echoing through the night, and above the tumult of their own voices they heard the old warrior calling on them to put into shore.  Mukoki was waiting for them when they landed.