"Then they are shooting our men," cried Bob. "They wouldn't be hunting when it's getting dark." "There's another shot," said the lieutenant, now growing as excited as his companion. "What shall we do?" "Fire a big gun," said Bob. "That would be letting our enemies know where we are," said the lieutenant. "Well," said Bob, sturdily, "let 'em know. It will show 'em that we are not afraid of them." "You are right, Roberts," said lieutenant Johnson, quickly. "Unshot the bow gun there." The gun was opened; the shot cartridge drawn out, a blank one substituted; and directly after, the black darkness that had seemed to settle down over them was cut by a vivid flash, and the utter silence that was brooding over the river was broken by the deep-mouthed roar of the great breech-loading cannon. The report seemed to roll off into the distance and echo amongst the mountains; and then, as it died away, they all listened with strained senses for some reply. It came, just as they expected--three rifle-shots in succession. Then a pause, and three more rifle-shots. There was a pause then, and the silence seemed awful, for the report of the great gun had driven every living thing near at hand to its lair. "Three marines," said the lieutenant, sharply, "fire as I give the order. One--two--three!" The three shots rang out at stated intervals, and the men reloaded and fired as before. Then they waited again, and the signal was answered in a peculiar way that left no doubt whatever in the minds of those on board, and a murmur of satisfaction ran through the little crew. And now, for the first time, Lieutenant Johnson began to wonder whether he had doubted the Malay guide without cause. He might have been swept overboard after all, and the hunting-party be really hemmed-in at some stockade. A few moments' consideration, however, showed that this could not be the case, for they had journeyed back many miles before the steamer ran aground; and though the river winded a great deal, it was impossible that the stockade could have been higher up. The firing certainly came from quite another direction, away from the river; and shots that were evidently not signals were now heard again--one or two, then three or four together, as if men were skirmishing, and then came several volleys. There was a fight going on, that was evident; and as the two officers realised this, they felt half-maddened at their helplessness.