"Look-see one, two, t'lee; he makee my hidee; my come this-side velly slow, galaw!"

In a few minutes the chief arrived, bearing his share of the burden. Both he and Ah-Sam were exhausted; in any case it was too late to attempt anything that night; and Bob told the men to eat and rest, for there would be work for them on the morrow.

When, next day, dusk was deepening into night, a sentry on the wall of the fort abutting on the ravine might possibly have seen, if it had occurred to him to look, a figure moving by almost imperceptible degrees along the face of the cleft opposite. The course followed was along a narrow ledge some feet below the top, leading from the inner end of the cleft to a spot immediately below the stout iron girder whose presence and purpose had given Bob so much food for conjecture. Arriving at the girder, the figure reached up, cautiously passed the looped end of a long rope over it, and, threading the other end through the loop, drew it tight over the girder and pushed it gently with the stripped branch of a sapling towards the centre. Then he retraced his steps along the ledge, carrying the loose end of the rope. The slack, dangling in the cleft, displaced a stone, which fell with a rattle to the bottom. The stealthy form hurried his pace to reduce the length of the slack, fearing for a moment lest the fall of the stone might have been heard in the fort. But there was little risk; stones must frequently drop down the sides of the ravine; and in any case the rope, in the almost total obscurity of the narrow cleft, was invisible from the farther side.

At the nearer end of the ledge Bob rejoined Ah-Sam and the chief, who were crouching by a couple of stout saplings that overhung the deep gorge beneath. Making fast to one of the saplings the rope he carried, he sat down and spoke in low tones to the Chinaman, explaining the scheme which he had devised after hours of meditation.

The situation was a simple one, yet one that called for nerve and unbounded courage. Immediately opposite the cleft, on the other side of the ravine, was the small rocky platform, with a staple in the wall above. The width of the ravine, as Bob estimated, was some eighty feet, but it was impossible to make any more accurate calculation; it might be more than eighty, it might be less; and a few feet one way or the other would make all the difference in the plan he had conceived. He had come to the conclusion that the iron girder which had so much piqued his curiosity had an intimate connection with the platform and staple. It had been there in the old chief's time; nobody knew when or why it had been placed in position, but Bob felt convinced that girder and platform had been intended to serve as a means of ingress to or egress from the fort if it should chance to be invested. A besieging force, relying on the apparent impossibility of scaling the side of the ravine, would be unlikely to maintain a guard there. But Bob's idea was that, suspended from a rope fastened to the girder, an active man could swing across the chasm, and, if the length of the rope were properly adjusted, could land gently on the platform, make good his footing by grasping the staple, and thereby prevent himself from falling backward with the return swing of the rope. If the rope were too long, he would of course run the risk of being dashed against the wall of the ravine beneath the platform. If it were too short, he would fail to reach the staple and swing back into the cleft; and as the return swing would obviously not carry him to his starting-point, he would again swing across the ravine, and so the pendulous movement would continue until he came to rest perpendicularly beneath the girder. He would then either have to climb the eighty feet of rope until he reached the iron bar, or drop the sheer two hundred feet to the bottom of the cleft. There was a further danger. On the return swing the man might, owing to oscillation in the rope, fail to enter the cleft, and be carried against its jagged edge, probably with sufficient force to stun, disable, or even kill him. Clearly the attempt would be full of danger; but it was this hazardous feat that Bob had resolved to attempt.

One necessary precaution could be taken in advance. It was to discover by experiment the length of rope needed. Bob guessed that the ledge on which he stood, at the narrow end of the cleft farthest from the ravine, must always have formed the springing-ground; its position therefore governed the length. Having explained to his two companions what he had in mind, he cut their expostulations short by borrowing some of their upper garments, which he made into a soft bundle. He weighted this with some heavy stones, tied it to the rope, and then, as the moon threw a dim light on the opposite side of the ravine, he placed the bundle in Ah-Sam's hands and made his way to the neighbourhood of the girder. Arriving there, he lifted his hand as a signal to the Chinaman to loose his hold on the bundle, and anxiously watched its course. It swept through the cleft, across the ravine, came to rest apparently within a yard of the platform, then swung back, making a giddy oscillation and narrowly escaping the wall of the cleft, until as it approached the ledge Ah-Sam caught it by means of a noose in a shorter rope. Its unsteady return journey gave Bob some alarm, but he surmised that with the greater weight of a man the rope would probably have risen higher and taken a more direct backward swing.

The experiment was sufficiently satisfactory, and then Bob explained to his amazed listeners what he proposed to do. He would himself risk the attempt. If he got safely across he would fix the rope to the staple and make a preliminary investigation of the pathway leading upwards from the platform. Should he require assistance he would return and loosen the rope, which would then swing back to a position perpendicularly under the girder. Ah-Sam meanwhile was to crawl to the extreme end of the ledge just below the bar; he was to obtain a hold of the rope as it swung loose, return to the innermost end of the cleft, and swing across the ravine as Bob had done. On the other hand, if Bob found that nothing could be done from the platform, or if he were detected, Ah-Sam was to cover his retreat with the revolver.

"What Sing-Cheng do allo tim'?" asked Ah-Sam when he had grasped his own instructions.

"He will remain behind. Tell him so."

When the chief understood this he was greatly indignant, and began to protest in loud tones. Bob checked him peremptorily. He felt that if he gained admittance to the fort precious time would be wasted if he had to give orders to Sing-Cheng through Ah-Sam, while if two men were unable to effect their purpose it was unlikely that three would succeed. He did not consider it necessary to argue with the chief, but pacified him by saying that, if Ah-Sam crossed over, he was to take the Chinaman's place at the end of the cleft and watch carefully lest it proved necessary to cover the retreat of the two from the other side.