They had already been pursuing the river course for four days, and, so far, it had withheld its secret. Somewhere out there on those wide shining waters a man was struggling in a great final effort to defeat once more the ruthless forces of Nature against which he had battled so long and so successfully.
And what would victory mean for him? Ross knew. Jack Belton knew. And their knowledge of that which was awaiting him, should a final triumph be his, added a deep depression to the silence which had fallen between them.
The great sun went to its death in a blaze of splendour, and the long Northern twilight softened the scene with misty, velvet shadows which crept down from distant hills to the north and south. The woodland bluffs, too, promptly lost their sharpness of outline, and the green of the trackless grass mellowed to a delicate softness which seemed to round off the peace of the airless evening.
Now they picked up the spiral of smoke from the camp-fire, and direction was promptly changed towards it.
"I sort of feel he'll make it," the Scotsman said abruptly, as though in simple continuation of his unspoken thought.
"You can't kill—him," replied the other emphatically. "I haven't a doubt. He guessed he could make the headwaters. He'll make them. I'm only scared to miss him in the night."
The doctor shook his head.
"I don't fancy that's going to happen. Our camp's always on the main water, in the open. There's our watch. No. I'm a deal more scared of him making a day camp, resting. Even then we haven't missed anything large enough to hide up a skitter."
"No."
Now the spot light of the camp-fire shone out of the soft twilight, and the sound of voices came back from the water's edge.