"Instinct?" repeated Dan blankly, "I dunno."
Calder grew serious.
"We'll take a chance that you may be right. At least we can ride down the river bank and see if there are any fresh tracks in the sand. If Silent started this morning I have an idea he'll head across the river and line out for the railroad."
In twenty minutes their breakfast was eaten and they were in the saddle. The sun had not yet risen when they came out of the willows to the broad shallow basin of the river. In spring, when the snow of the mountains melted, that river filled from bank to bank with a yellow torrent; at the dry season of the year it was a dirty little creek meandering through the sands. Down the bank they rode at a sharp trot for a mile and a half until Black Bart, who scouted ahead of them at his gliding wolf-trot, came to an abrupt stop. Dan spoke to Satan and the stallion broke into a swift gallop which left the pony of Tex Calder labouring in the rear. When they drew rein beside the wolf, they found seven distinct tracks of horses which went down the bank of the river and crossed the basin. Calder turned with a wide-eyed amazement to Dan.
"You're right again," he said, not without a touch of vexation in his voice; "but the dog
