Again the fearful scream pierced the air. Isobel looked quickly across towards the far side of the cañon. She could see nothing, but she drew in a deep sigh of relief. The second cry had told her that it was only a mountain lion, over on the other brink of the chasm.
When she again looked down at Ashton he was descending a crevice with a rapidity that brought her heart into her mouth. Yet there was no hurry in his 369 quick movements, and every little while he paused on a shelf to peer at the steep slope immediately below him. Soon the circle of lantern light became smaller and dimmer to the anxious watcher above. Steadily it waned until all she could see was a little point of light far down in the darkness––and always it grew smaller and fainter.
Lying there with her bosom pressed against the hard stone, her straining eyes fixed on that lessening point of light, she had lost all count of time. Her whole soul was in her eyes, watching, watching, watching lest that tiny light should suddenly shoot down like a meteor and vanish in the darkness. Many times it disappeared, but never in swift downward flight, and always it reappeared.
Not until the moon came gliding up above the lofty white crests of the snowy range did she think of aught else than that speck of light and of him who was bearing it down into the black depths. But the glint of moonlight on a crystalline stone broke her steadfast gaze. Before she could again fix it on the faint point of lantern light a sound that had been knocking at the threshold of her consciousness at last made itself heard. It was an intermittent clinking as of steel on stone.
She looked around, thinking that one of the horses was walking along the ridge slope with a loose shoe. But all were standing motionless in the moonlight, 370 dozing. Again she heard the click, and this time she located the direction from which it came. She looked at the split rock on the edge of the sheer drop. From beside it she had peered down through the field glasses at the outstretched form of her brother, far beneath in the cañon bottom.
The sound came from that rock. She stared at the side of the frost-split fragment with dilated eyes. The crack between the loose outer bowlder and the main mass showed very black and wide in the moonlight. Could it be possible that it had widened––that it was slipping over? And her brother down there beneath it!...
By setting wedge-shaped stones in the top of the cleft rock and prying with the crowbar, Gowan had gradually canted the top of the loose outer bowlder towards the edge of the precipice. It had only to topple forward in order to plunge down the cañon wall. He was working as silently as he could, but with a fierce eagerness that caused an occasional slip of the crowbar on the rock.
Although the great block of stone weighed over two tons, its base was small and rounded, and the mass behind it gave him leverage for his bar. Every inch that he pried it forward, the stones slipped farther down into the widening crack and held the vantage he had gained. Already the bowlder had been pushed 371 out at the top many inches. It was almost balanced. The time had come to see if he could not pry it over with a single heave.
He did not propose to fall over after the rock. He turned his face to the brink, set the end of the bar in the crevice, and braced himself to heave backwards on the outer end. He put his weight on it and pulled. He could feel the rock give––the top was moving outward. A little more, and it must topple over.