Jacques, used as he was to extreme and violent exercise, was beginning to fail. On route marches, it is true, he had often done forty kilometres heavily laden. They were not yet forty kilometres from their starting-point, and he was carrying nothing, but it must be remembered that the Legion on the march pauses often for a rest and that five minutes' rest makes all the difference. Jacques had not had a moment's rest. The same held true for Mansoor. Both men were exhausted, but they were exhibiting the effects of their exhaustion in different ways. Jacques, marching well and firmly, had the appearance of a man still capable of covering many miles. His legs were still all right, but his head was giving out. The higher nervous centres could not hold to their work much longer, and that is one of the most fatal forms of exhaustion. For half a minute at a time he would forget Mansoor. At any moment he might fall together like a house of cards and lie on the ground, not dead, but sleeping peacefully, a prey to the man he was pursuing. On the other hand, Mansoor was failing in the legs; occasionally he swayed and stumbled, but his mind was clear and it dominated his body, as a jockey dominates an exhausted horse. They had entered a little gully where years ago quarrying work had gone on, for stone to metal the great south road, and Jacques' mind had just returned from one of its momentary lapses, when he saw the man he was pursuing wheel round and advance towards him. Mansoor was holding something in his right hand. It was an automatic pistol. It was the sight of the pistol that brought Jacques' mind vividly awake. A pistol! And he had been absolutely certain that his enemy was unarmed. The fact remained, and before the fact Jacques turned tail. But he did not run. On his left a cave-opening in the rock caught his eye, and urged by the dread of a bullet in his back he dived into the cave. Mansoor, pistol in hand, came along, swaying as he came, wild-eyed and dreadful, with the grey pallor of exhaustion showing through his dusky skin. Right opposite the cave mouth, and thirty feet or so away, he flung himself down on the ground, rested his left arm on a piece of rock and the barrel of the pistol on the angle of his elbow, taking aim straight into the cave. Jacques, seeing this, flung himself flat on the cave floor and waited for the first shot. But Mansoor did not fire. He seemed content to lie recovering from his exhaustion and holding his enemy at bay. Jacques had retreated as far as possible into the darkness of the cave, the opening was some nine feet or so from his face, and as he lay on his stomach, his chin resting on his arm, the fact that he was cornered and at the mercy of the other appeared before him in all its bleak simplicity. Mansoor, when he had rested sufficiently and gauged the possibilities of the situation, would come straight to the cave mouth and then all would be over with Jacques.