The moat encircling the Fort was twenty-eight feet wide and eighteen deep. Strongly fortified everywhere, a special feature of its strength lay in the caponiere gallery. The walls of this gallery, constructed beneath the entire counter-scarp, were some seven feet thick. On this, the South side, as also on the East, the gallery was divided by concrete partitions into five communicating cells or chambers. These chambers, as Lieutenant Helmore knew from the confidential plans of the defence works, communicated, cell with cell, by low and narrow doorways. From the last of the five cells, by a narrow flight of steps, could be reached a door of massive steel, and on the other side of that door a passage five feet wide passed beneath the rampart and the moat into the interior of the Fort itself. This communication, of course, was intended to enable defenders of the Fort to reach the caponieres which jutted into the moat at intervals, and thence fire upon any troops that sought to bridge it. The enormous importance of his discovery made Helmore forget for a moment the fate or peril of his ill-starred comrades--buried as they were in the adjacent débris. Indeed, it was apparent that nothing could be done for them. Their dreadful fate was sealed, and the faint groans that at first reached the ears of the would-be rescuers soon entirely ceased to be heard. Helmore, after a moment's pause, sent a man back with news of the discovery to his commanding officer, who instantly grasped the requirements of the situation. He issued certain rapid orders, and a hundred men darted down the hill in prompt obedience. Meanwhile, the relief sappers, guided by Helmore, crept through the narrow tunnel into which an opening had been forced by the explosion. Without losing an instant, the Engineers began to chisel several holes in the exposed section of the concrete wall. A charge of dynamite was passed along, and all made ready. The men rushed back and waited. The crack and crash of a violent explosion followed, and the sappers, hurrying forward, followed by other troops, found that a broad gap had been made in the gallery of the caponiere. Through this breach they crept and crawled, to find themselves in the first of the five cells, or gallery-sections, that have been described. Opposite to them was the arched doorway leading into the next chamber. But already the defending force had occupied it. Foreseeing that the entire gallery might be rushed chamber by chamber, they had brought heavy sandbags and piled them high, close to the first doorway.