The Marines assented cheerfully. No harm in humoring this poor devil of an officer who had crashed and lost his wits. Like Luke Evans, shambling up through the line to Dick's side. Dick advanced. At any moment now the concentrated fire of the Emperor's men should blast them all to smithereens. Nothing happened. And it was no dream, for Dick's outstretched hand encountered the exterior wall of the building. He had gauged his way accurately, too, for a step or two brought him to the door. He stepped inside. He was inside the private door that led to the Emperor's quarters, through which he had passed with Fredegonde, Hargreaves, and Luke Evans in their flight. It had been broken down, contrary to the girl's predictions, and the deserted passage within was perfectly visible to them all. Stupefied, the Marines bumped and jostled with each other as they crowded in. If they had been anything but Marines, their own heads might have been turned at the discovery of this sudden materialization of a building out of nothingness. Being Marines, they only grinned sheepishly, and followed along the corridor. * * * * * The first human being they saw was one of the guards, in a black tunic. He was leaning against a wall, and he was a human being no longer. He looked as if he was asleep, but he was stone dead, with a placid look on his face. Two more dead guards lay across each other, with smiles on their faces: and there was a workman in a blue blouse who had been in a tremendous hurry to get somewhere, from his appearance, and had never got there. He had fallen asleep instead, and never wakened. Dick found a stairway and led the way up. He thought it ran up to the laboratory, but, instead, the room into which he emerged was the ante-room of the Invisible Emperor's audience hall. Six dead guards lay in a heap in front of the curtain, and they had died as unconcerned as their fellows, to judge by the pacific expressions on their faces. Dick passed through into the throne room. The Marines, behind him, for the first time uttered exclamations of awe--of pity. The terrific scene that met Dick's eyes would be burned into his brain till his last day. Upon his throne, head flung back, sat the Invisible Emperor, his features set in a sardonic leer of death. And all about him, some sitting, some lying, supporting one another, were his court, officers in black uniforms with the silver braid, and women in court dress. And all were dead too. But they had not known they had died. They had fallen asleep--upon the instant that their own volatile gas reached them. * * * * *