He fell farther and farther behind Iskwao, and twice lie turned, his fangs gleaming under drawn lips, and his defiance rolling back upon his enemies in low thunder.

When he came up out of the coulee he was in the shadow of the peak, and Iskwao had already disappeared in her skyward scramble.  Where she had gone was a wild chaos of rock-slide and the piled-up debris of fallen and shattered masses of sandstone crag.  The sky-line was not more than three hundred yards above him.  He looked up.  Iskwao was among the rocks, and here was the place to fight.  The dogs were close upon him now.  They were coming up the last stretch of the coulee, baying loudly.  Thor turned about, and waited for them.

Half a mile to the south, looking through his glasses, Langdon saw Thor, and at almost the same instant the dogs appeared over the edge of the coulee.  He had ridden halfway up the mountain; from that point he had climbed higher, and was following a well-beaten sheep trail at about the same altitude as Thor.  From where he stood the valley lay under his glasses for miles.  He did not have far to look to discover Bruce and the Indian.  They were dismounting at the foot of the coulee, and as he gazed they ran quickly into it and disappeared.

Again Langdon swung back to Thor.  The dogs were holding him now, and he knew there was no chance of the grizzly killing them in that open space.  Then he saw movement among the rocks higher up, and a low cry of understanding broke from his lips as he made out Iskwao climbing steadily toward the ragged peak.  He knew that this second bear was a female.  The big grizzly—­her mate—­had stopped to fight.  And there was no hope for him if the dogs succeeded in holding him for a matter of ten or fifteen minutes.  Bruce and Metoosin would appear in that time over the rim of the coulee at a range of less than a hundred yards!

Langdon thrust his binoculars in their case and started at a run along the sheep trail.  For two hundred yards his progress was easy, and then the patch broke into a thousand individual tracks on a slope of soft and slippery shale, and it took him five minutes to make the next fifty yards.

The trail hardened again.  He ran on pantingly, and for another five minutes the shoulder of a ridge hid Thor and the dogs from him.  When he came over that ridge and ran fifty yards, down the farther side of it, he stopped short.  Further progress was barred by a steep ravine.  He was five hundred yards from where Thor stood with his back to the rocks and his huge head to the pack.

Even as he looked, struggling to get breath enough to shout, Langdon expected to see Bruce and Metoosin appear out of the coulee.  It flashed upon him then that even if he could make them hear it would be impossible for them to understand him.  Bruce would not guess that he wanted to spare the beast they had been hunting for almost two weeks.

Thor had rushed the dogs a full twenty yards toward the coulee when Langdon dropped quickly behind a rock.  There was only one way of saving him now, if he was not too late.  The pack had retreated a few yards down the slope, and he aimed at the pack.  One thought only filled his brain—­he must sacrifice his dogs or let Thor die.  And that day Thor had given him his life!