He had interrupted himself to gaze across the canyon. The great brown hound stood on the opposite rim. Silently he had come out of the forest; silent and perplexed, he sniffed the air, testing its scents. As they watched, his body suddenly stiffened and his tail went straight as a poker. His ears laid back and his teeth bared, and then a volleying bark rang out across the canyon. Ruler pawed the ground in his excitement--then he suddenly ceased and ran along the rim, a houndy growl, whimpering with eagerness, coming from him. “That settles it!” said Scotty, rising energetically. “He _saw_ the Black Panther, Sid! His eyes are sharper than ours. That brute’s around here, somewhere, behind us or above us--did you note where Ruler seemed to be looking?” Both boys were now alert and warned. They stepped slowly along the roof, toward the ladder end of it, rifles poised, eyes scanning every possible lurking place. “By--_Gosh!_--There he _is_!” yelled Scotty in a sudden scream of fright. “Mark!--_Cliff!_” He had jumped back as Sid looked up, bewildered. Thirty feet over their heads, on the sheer face of the cliff where grew out the stubby roots of a spruce from a crack, crouched the great cat. His eyes smoldered green fire as he peered down at them over the root, and his pink mouth opened in a hideous, silent snarl. Then his ears flattened back. “Shoot! He’s going to jump!” barked Sid, his rifle springing to shoulder and crashing out as the bead swung up over a confused mass of black. Down through the smoke that long, lithe shape plunged like a plummet, a brawny forepaw stretched out, with the five talons outspread like steel hooks. Both boys leaped back rapidly across the roof, for when he landed he would rebound like some deadly infernal spring-machine at one of them. It was a diabolical black head,--the nose a snarling mass of wrinkles, the eyes spitting savage ferocity, that turned on Scotty with the quickness of a lightning flash when the Black Panther hit the roof. His attack was bewildering, a series of short springs, each a smash of the muscular forepaw, each a wicked snarl of formidable fangs and a hoarse, hissing cat-spit that nearly paralyzed Scotty with fright. The youth jumped back, the cat following, sparring at him as he pranced on three legs. It was impossible to get the gun muzzle up, as the sweep of that paw would have knocked it spinning out of his hands. Yet during the short five seconds of that rush Scotty was aware of the constant baying of a hound and the shouts of Sid to jump clear to one side so he could fire. Then a frightful blow, that ripped his sombrero brim and tore it from his head, sent his rifle up instinctively to ward off, and the next instant it was struck from his hands, bellowing like a cannon as the trigger jarred loose.