The party now slowly retraced its way to camp. In speculating about the greater mystery they appeared to have forgotten the recent ghostly disturbances in the camp, though it was pretty generally understood that the latter incidents were due to a prank of one of the boys. That one boy, as the reader already surmises, was Tad Butler. Tad had evened his score with the fat boy for all the latter's pranks on him and the others, and Stacy knew it. The fat boy was shrewd. He said no more about his fright, but Tad observed that Stacy frequently cast reproachful glances in his direction.
Tad remained on watch for the rest of the night. They made an early start on the following morning, and, as on the previous day's journeyings, they found rough going all the way, with great rocks towering high above them, cut here and there by frequent deep, gloomy canyons.
About noon of this day as they were slowly riding through one of the rifts in the mountains, they pulled up sharply at a signal from Tad.
"What is it?" demanded the Professor, realizing that Butler had made a discovery.
Tad pointed ahead of them. The Professor gazed in the direction indicated.
"Fog?" he asked.
"I think not. It looks to me like smoke," answered the Pony Rider Boy.
"Who, Smoke Griffin?" piped Stacy in a loud voice.
"No, just plain smoke. And if you please, don't speak so loudly," admonished Tad.
"Hm-m-m. What would you suggest?" asked the Professor.