"Well," replied Saracen, "I guess that's right enough. You've just come to see the Sierra country. We're not going to stay long on this side, and after I get through with this little bit of peak--which was the reason of the crossing that stream--we shall go to the other side of the mountain, where I can put you on the main trail. By that means you will have a couple of weeks up here, and still be able to get back to the Canyon to finish that bit of work you are pledged to do there." Roger thanked him heartily, and began his ten days of mountain climbing, an experience utterly new, for even the scrambling up and down the terraced cliffs of the Colorado was a different matter from the scaling of apparently inaccessible crags, where the climber faced no little peril in making the ascent. Further, in order to do the drawing after he got up, he would have to be tied on and have the plane table tied, while working on a knife-blade ledge all day. Some few days after his arrival, Roger had the unexpected opportunity of seeing a mule train possessed by fear, and watching a mule buck. Mules rarely buck, so the lad was conscious of the value of the experience. It happened on a fairly wide trail, but which sloped considerably to the side of the mountain, and Roger was riding beside the chief of the party. Suddenly a loud commotion was heard in the rear of the pack train, and Saracen and Roger reined up. Duke, always restive and nervous, began to prance about, showing evidence of real fear, and while Roger was a good horseman and kept his seat easily, he could not keep the beast on the trail, and the bay danced off to the side, where on the turf, three or four yards from the beaten track, he brought him, snorting and trembling, to a standstill. Then he had time to look about him. On the trail immediately above him, the lead mule, bestridden by Saracen, was performing evolutions that would not have disgraced a trick circus beast, cavorting and pirouetting and bucking, evidently longing to bolt, but held down by the iron hand of his rider. Just as the beast was a little quieted and Roger thought of resuming the trail, there came a clattering of hoofs, and whish! a runaway mule flashed by, arousing Duke and the lead mule to a new exhibition of bucking. Roger soon had his mount pacified, but Saracen was getting angry, and was applying whip and spurs without stint, to no purpose, for a couple of minutes later another of the pack train's mules came down tearing up the dust, then two together in a panic of stampede.