They leaned over the pile which they had accumulated close to the top of the steps, and filled an arm. Then, with one ready in their hands, and a sufficient space between them to give ample room for throwing, they waited. By now the fire had commenced to burn up a little, and the flames illuminated the top of the stairs feebly, showing the big jars of earth. Roger watched them, and heard whispering, for the Mexicans had also seen the obstruction. Then a man's head squeezed between two of them, while his body slowly wriggled its way through the narrow opening. A second appeared at another, while a third, a venturesome fellow, clambered round the outside margin of the one which stood on the very border of the steps. A slip of the hand, a toppling of the jar, would have sent him into space, with a fall of some hundreds of feet below him. Roger lifted his arm, aimed for the central man, and launched his brick. There was a dull thud, a shriek--more of fear than of pain--and the Mexican withdrew. Then Tamba attempted the same, and with equal fortune, his brick glancing from the man's back and clattering down the stairs. As yet not a sound other than the shriek had come from either of the combatants. But now a voice was heard. Some one gave a sharp order, and at once an attempt was made to repeat the process of wriggling through, while, on the side nearest to the centre of the tower, arms encircled the jar, and an effort was made to remove it. But Roger frustrated the attempt, a well-aimed brick crashing against one of the arms, and breaking it as if it had been a stick. Meanwhile Tamba had pelted the others, and had caused them to withdraw. "They are talking again," whispered Roger, as he crouched in the darkness. "We will remain here till they attempt to remove the jars, and then we will use our swords. Make no noise, but cut at them with all your strength. If they become dangerous, wait for my shout, and then do what I order." There was a lull for some few minutes, while the ever-brightening fire permitted the defenders to see that no one was at their obstruction. But down below an occasional dusky figure could be observed, while there was the dull sound of whispered conversation, and a click now and again as a club or sword struck the masonry. Suddenly there was silence again, and Roger nudged Tamba. "A sure warning," he whispered. "Get your sword ready. But one second. Can they possibly reach us in any other way?" "It is out of the question, master. The walls are steep and smooth, and there is no one to lower a rope. We have only the stairs to defend." "Then I have little fear. If I were unarmed I could hold them, I think, unless they came prepared to cut us down. That would be different."