Chagres, as has been said, was built on a high hill close to the river; it was surrounded by strong palisades buttressed with earth, and a ditch thirty feet deep defended its near approach. It had but one entry, and that reached by a drawbridge over the said ditch. Four bastions looked landward and two seaward. On the north side ran the river, and on the south the hill was too steep for any invader to climb. At the foot of the mountain was another fort with eight guns commanding the river, and two other batteries were placed a little lower down. This, then, was the well-fortified place which the pirates were now determined to possess themselves of; and no wonder that Carlo spoke rather scornfully to Harry of the expedition as an impossible and rash dream. ’My uncle, Don Alvarez, is as wise and brave a man as can be found in all the dominions of the King of Spain,’ he whispered to his companion, when the two were left alone, unnoticed by the excited sailors. ’I have seen enough of these men, Señorito, to make me disbelieve in nothing. They will leap down headlong into danger, and get up unhurt. But I see they are not making straight for the mouth of the river; doubtless we shall land a little way off, so as to avoid the fire from the fort.’ ’If I could but warn my uncle!’ said Carlo earnestly. ’Look you, Master Harry Fenn, I will give you a handsome reward if----’ Harry tossed back his fair hair even as a young colt who is galloping before the wind, as he answered: ’You forget, Señor, that though I may be among thieves, yet I am an honest Englishman, and I take no reward for doing what I can. I am no knave that gripes after a reward.’ Carlo saw that he had insulted the boy who had saved his life, and with his usual impetuous generosity he apologised fully. ’Indeed, indeed, I meant no harm. I am sorely troubled; but you at least will forgive me. This luckless affair has made me foolish.’ Harry was easily pacified, and he himself at once suggested a plan by which Carlo might accomplish his purpose. ’Look now, Señor Carlo: when our ships come to anchor, they will put more than half the men ashore in order to carry the castle by assault, and they will not trouble themselves much about us, I see. If we could escape then, and go faster than the attacking party, we might do some good in warning Don Alvarez.’ ’Yes, that is indeed a first-rate idea, and that also reminds me that, close by the landing at the foot of the castle, there is a small steep staircase cut out of the solid rock. I have often climbed up by it for quickness when I have been staying with my uncle and was late for supper. If we could somehow get there, trust me to distance them. What think you of this possibility?’