The young man whistled when he saw how near they had come to a hideous death. Several times he had seen the bodies of men who had been suddenly exposed to the pressureless airless cold of the outer void--hideous bloated things through whose skin the livid blood had forced its way. "Any luck, Jan," he asked, looking back at his companion. "Did you find some cement?" She shook her head. CHAPTER VI The Space Men Attack First stepping to the oxygen supply valve and opening it a trifle wider, Shelby hastened to assist the girl in her quest. Their ears were ringing. The air pressure within the hull was dropping rapidly. Diligently they ransacked every nook and corner, but found nothing more valuable than a can of thick grease. Shelby smeared some of it over the crevice; it helped but did not by any means check the flow of the escaping air entirely. "It's a race with time now, Jan," he said quietly. She looked at him. Her face was a trifle pale, but her lips and eyes were smiling. "Are we on our way to Mars, Captain?" she enquired. He nodded. "We are, Admiral. The fuel tanks are full and if our air lasts we'll get there." "And when we do," she put in, "the best of luck to Hekki and his friends!" A vision swept through Shelby's mind--batteries of fantastic machines whose maws spewed flames of faint lavender fire--blinding flashes of light and world-rocking explosions: a hideous thing to dream of--hideous yet glorious, for the civilizations and freedom of two worlds depended upon it. To the Red Planet--they _must_ make it! Janice Darell had placed her hand lightly on Shelby's arm. Her expression was serious, almost hard. "Austin," she said, "tell me truthfully, can we really reach Mars? It is likely that we shall get there before we go out?" "Certainly, darling," he replied, putting as much assurance into the words and expression as was possible. "Why do you ask?" There was something that suggested doubt, perhaps even displeasure in her answer: "We have a duty to perform, Austin--a duty infinitely bigger than our own petty existences. You have not seen what I have seen--small scouting patrols that came to the _Selba_ riding strange round things that must have been machines of some kind. One look at those henchmen of Alkebar, their great black bodies, their quick nervous movements--like eager panthers, their wicked-looking weapons which they carried with such an air of easy assurance, and you would have known what they hoped to do. Most of these devils are within the orbit of Mars for the first time. Certainly Hekki has told you something about them?" Shelby nodded. "Very little; but I have noticed a few of Alkebar's remarkable peculiarities," he said. "Well," she continued, "if we can't get to Taboor, there is one thing we can do--destroy the _Selba_, and with it Hekki and Alkebar."