The two reached the foot of the tower and laid their burden down--gently, as befitted a box containing precious porcelain--at the door. Then one of them stooped lower, and appeared to thrust something into a hole near the bottom of the box. The watchman on the wall must have been half-asleep, or he would have noticed a sudden spark at the foot of the tower. It flashed but for a moment; then the two men, bending low, hastened back stealthily by the way they had gone, came to the change-house, and slipping in by the still half-open door, closed it behind them. They waited for perhaps a minute, and there was not a sound within the guest-chamber save the slight smothered grunting of the Afghans through their gags. Then from without there came a sudden roar; the ground trembled, the building rocked as if it would fall about their heads, and the waiting men, drawing a long breath, threw open the door and ran with great nimbleness towards the tower The street was filled with acrid fumes; here and there men were crying out, but the merchants paid no heed, but rushed through the smoke and plunged into the yawning chasm where the tower door had been. The opening was clogged with burning wood and fragments of masonry; the intruders stumbled over these, coughing up the smoke that entered their lungs, and groped their way up the narrow winding stairway. Cries from above assailed them. At the top of the first flight of steps stood a man armed with a long spear. The stairway was so narrow that only one man could pass at a time, and the man at the head of the mounting party, coming too suddenly upon the spearman, received a thrust in the breast and toppled backward. But the man behind him slipped aside to avoid his falling body, and caught the spear before it could be withdrawn, dragging the spearman forward. Two others--they were Sherdil and Ahmed--seized the occasion to squeeze past him; but they gained the top of the flight only to see the two men who, behind him, had been content to let him bear the brunt of the attack, dash back across the narrow passage to a door on the other side. The passage was lit by a small oil lamp--a wick floating in a shallow saucer. By its light Sherdil and Ahmed saw the men fling themselves through the door into the room beyond. They sprang after them, but the door was slammed in their faces and the bolt shot.