Till dusk he waited, thinking, puzzling. The first move must be to spy out the position—the surroundings of the fort, especially the ravine. He resolved that this was a task for himself alone; the risk of being seen would be trebled if he took his companions. He wondered whether the moon would give him light; without it he could discover little or nothing, with it he might himself be discovered. The afternoon had been cloudy; a high wind had swept dense cumulus across the sky; but the cloud mass had been broken, not continuous, and the fitful gleams he might expect if the moon rose would serve his purpose better than a steady shine. It was not yet dark when he started, but sufficiently gloomy. "Wait here till I return," he said to Ah-Sam. "If you are discovered, save yourselves as best you can." He crept cautiously down the long slope. Shrubs, mounds, irregularities in the soil, gave him cover for a considerable distance. A belt of low trees apparently fringed the ravine; if he could gain that, he thought he would be safe. He came to it, passed through, and found that it did not extend quite to the edge of the ravine; a space of a few yards had at some time been cleared, but was now becoming overgrown with brushwood. He threw himself on his face, crawled behind a thick clump, and found himself on the brink. For a few moments he waited, wondering whether, as’ he moved, his light-coloured garments had been descried from the fort. He heard the sound of many voices from the other side, the whinny of a horse, the clink of metal; but there was nothing to indicate any unusual circumstance, and drawing himself a little forward, still keeping as much as possible in the shadow of the bush, he peeped over. The ravine was deep, deeper even than he had expected. Even in the gloom he could see its opposite side and the walls of the fort, but he could not see the bottom of the ravine; he only heard the swirl of the water over the rocks far below, and fancied he could just discern an occasional dash of white foam. Opposite rose the grim wall of the fort. Bob scanned it anxiously for the sign of a sentry; there was none. He realized that none was needed. Below the fort the ground shelved rapidly for several yards to the edge of the ravine, then bent inwards before it became a perpendicular wall to the invisible bottom. Bob looked all along the space from left to right, and marked one spot where the inward curve was broken by what appeared to be a horizontal rocky platform, like those large flat slabs sometimes encountered exceptionally among jagged rocks on the sea-shore. Beyond this platform, up the shelving bank, he espied a narrow winding path which was visible for a few yards, then disappeared into the face of the cliff to the left of the fort. In the cliff-wall itself, just above the platform, he caught sight of what appeared to be an iron staple, though this seemed so unlikely that he thought his eyes might have deceived him.