“Do you not see,” he said, “that it is quite possible that their fleet may be twice as strong as ours, and that in spite of all our gallant forlorn hope can do they may cross the mountains and send their shells into the valley? “What if one of them exploded here and wrecked the outworks and the entrance to the caverns? All hope, even for us, would then be lost, the doors could not be lowered, and we should either have to let the waters of the lake flow out or they would flow into the caverns by the upper entrance and ruin all our labours. “We have proved that the _Alma_ and the _Isma_ are the two best air-ships in existence. They can soar higher and travel faster than any others. Would it not be madness to deprive our defending force of them, and would it not be cowardice in us not to do all we can to save all that is left for us to hope for on earth? I for one shall go, and I don’t believe that I shall go alone.” “If the _Alma_ goes the _Isma_ goes too,” said Alexis. “Alan is right. We should be cowards to turn our backs on the enemy at the last moment.” “And if you go, we go,” said Alma and Isma in a breath. “If you live we will live with you, but we will not live without you.” There was no answer to such reasoning as this, nor was there any longer any law on earth save that of individual will. The first motive power that had swayed the world was the last that survived and would be the last to die. Those of the old crews of the two air-ships who were found among the chosen at once came forward to take their places, and with them came too those who had elected to take the hazard of life or death with them. “There shall be no widows in the new world,” said they. And so every man who rose into the air on board the two great warships carried with him the woman without whom the one last chance of life would not have been worth taking. As they left the earth the remainder of the little company retired into the caverns, leaving two sentinels posted at the outer door ready to give the alarm in case it should be necessary to lower the doors. As they did so a long, dull, distant roar came from the northward telling that the last battle of man with man had begun. In accordance with a plan hastily arranged before they rose, the _Alma_ was to guard the northern end of the valley, while the _Isma_ kept watch over the southern. They soared up and up until the peaks of the mountains were a good five thousand feet below them. From this elevation those on board the _Alma_ could see the enemy’s fleet stretching out in a huge crescent, made up of tiny points of light which shone in the unnatural glare that illumined the earth and sky, and ever and anon they saw enormous spheres of flame blaze out along the line as the projectiles from the land batteries burst in front of them. The gunners were only trying their range and the enemy were still beyond it.