“Let’s breathe the horses a little,” proposed his friend. “There’s no particular hurry, goodness knows! I hate to go back to Silver Run and tell mother just how the matter stands. It’s a terrible thing, Dig.” “I know,” muttered his chum, and walked away, unable to talk about Mr. Havens’ peril in the caved-in mine. Dig walked to the brow of a sharp slope. The opening into the Crayton mine was on a small plateau, one side of which gave right up on the steep slope of the mountain. Landslides in the past had raked this side of the mountain quite bare. Here and there a ledge cropped out, or a boulder, in rolling down the slope, had found lodgment; the trees that had taken root in the thin soil were stunted and the bushes meagre. Digby rested a booted foot upon a boulder that hung poised upon the very edge of the plateau. He leaned forward to look down the hill, and as he did so he felt the huge stone tip forward. “Whew!” he ejaculated, leaping back, expecting to see the boulder slide over the precipice. “What’s the matter, Dig?” demanded Chet, turning to look at him. “Look there!” and the other pointed to the boulder, which, instead of slipping over the edge, rocked back into its bed, and dipped again and again while it gradually settled into its usual position. “A rocking stone,” said Chet with a smile, seeing that his chum was greatly excited. “What about it?” “Whew!” and Dig expelled his breath as he frequently did to express emotion. “I thought I was a goner. The old rock pitched forward as if it were going to dive right down the side of the mountain.” “If it ever does get the right push,” said Chet, looking down the slope, “it will start something. It’s a big one—and if it hits that gully yonder,” pointing to a groove in the mountainside below, that marked the course of some ancient avalanche or watercourse, “it will tear straight down to the foot of the mountain—and that’s ten miles, Dig, if it’s an inch.” “Uh-huh!” admitted his chum. “Be some ruction. I’d like to see it.” He rested his weight on the rocking stone again and tried to throw it forward; but its balance seemed perfect. Just the same, when they mounted their horses and took the back track for the Silent Sue, the rocking stone still was balancing to and fro as though about to plunge over the brink of the plateau. From the level of the caved-in shaft the boys descended a slanting path just within the border of the forest. Through openings in the trees on the right hand they occasionally caught a view of the avalanche-swept space which they had seen a few moments before from the higher level. Chet’s thought was naturally upon the trouble at the Silent Sue and his father’s fate; so it was Dig, visually the less observant, who stopped his mustang suddenly and put out a warning hand to his chum. “Hey! look there!” said Dig.