“You’re certainly welcome, so far as I’m concerned, Taggert,” said Robert, agreeably. “Only you might have to share some scanty rations before we land.” “Shan’t mind that,” was the reply. “Brought some myself to help out.” He picked up a good-sized cubical package from where he had set it down a few minutes before. “Bouillon cubes, malted milk tablets, and chocolate,” he explained, tapping the parcel. “Fair enough,” said Robert. “Boys,” interrupted the professor, “take a look at old Mother Earth now.” With one accord they hurried to the windows to gaze upon the receding Earth, which for a minute they had almost forgotten. The wavering altimeter indicated a height of more than 125,000 feet--almost twenty miles! The semi-luminous Earth far below them now presented a dull, nebulous appearance, devoid of landmarks, except that far to the southeast a faint thread of lighter color wound its way irregularly across the country; this they judged to be the Ohio River. One other distinguishable mark was a small, dimly illuminated patch indicating the city near the laboratories. “Good old Earth, good-bye,” said Taggert. His customarily cheerful voice contained a note of awe. Indeed, the sight was sufficient to strike awe into anyone’s heart; but then, Taggert was thinking, too, of a certain dark-haired and brown-eyed lass who would be waiting anxiously for him to return to her. At the end of a fifteen-minute wait, basing his estimate on their former rate of ascension, when the altimeter was still registering accurately, Robert calculated that they had reached a distance of approximately 150 miles above the Earth. At this distance the atmosphere should be sufficiently thinned to eliminate it as a factor of interference with their course or danger of air friction. He could now safely utilize the disk’s full magnetic power. With the resistance of the atmosphere reduced to nothing, their speed was doubtless already increasing, and with the maximum pull of the disk developed by the current from the storage batteries, their velocity would quickly double and redouble until they were rushing through space at a terrific rate. Thus would they continue exactly like a planet until checked by the attraction of some other body or a readjustment of the disk. Just how great a velocity they might obtain they had been unable to determine accurately, but it was considered not improbable that the _Sphere_ might reach Mars within a month. Under Professor Palmer’s guidance Robert now laid their course for Mars, carefully focusing the disk upon it. The full propulsive force of the disk was about to be used for the first time. All three watched tensely through the windows as Robert prepared to throw on the switch that would charge the mythonite with electricity. An answering jar was felt as contact was made with the first terminal. By degrees, their velocity was increased until the full energy of the powerful batteries was diverted into the disk.