"Easily, if the vitalium holds out, and if we don't collide with a meteorite. There is no limit to speed in space, certainly no practical limit. Acceleration is the important question."
"We may collide with a meteorite you say? Is there much danger?"
"A good deal. The meteorites travel in swarms which follow regular orbits about the sun. We have accurate charts of the swarms whose orbits cross those of the earth and moon. Now we are entering unexplored territory. And most of them are so small, of course, that no telescope would reveal them in time. Merely little pebbles, moving with a speed about a dozen times that of a bullet from an old-fashioned rifle."
"And what are we going to do if we live to get to Mars?"
"A big question!" Brand grinned. "We could hardly mop up a whole planet with the motor rays. Trainor has a few of his rocket torpedoes, but not enough to make much impression upon a belligerent planet. The Prince and Trainor have a laboratory rigged up down below. They are doing a lot of work. A new weapon, I understand. I don't know what will come of it."
Presently Bill found his way down the ladder to the laboratory. He found the Prince of Space and Dr. Trainor hard at work. He learned little by watching them, save that they were experimenting upon small animals, green plants, and samples of the rare vitalium. High tension electricity, electron tubes, and various rays seemed to be in use.
Noticing his interest, the Prince said, "You know that vitalium was first discovered in vitamins, in infinitesimal quantities. The metal seems to be at the basis of all life. It is the trace of vitalium in chlorophyl which enables the green leaves of plants to utilize the energy of sunlight. We are trying to determine the nature of the essential force of life—we know that the question is bound up with the radioactivity of vitalium. We have made a good deal of progress, and complete success would give us a powerful instrumentality."
Paula was working with them in the laboratory, making a capable and eager assistant—she had been her father's helper since her girlhood. Bill noticed that she seemed happy only when near the Prince, that the weight of unhappiness and trouble left her brown eyes only when she was able to help him with some task, or when her skill brought a word or glance of approval from him.
The Prince himself seemed entirely absorbed in his work; he treated the girl courteously enough, but seemed altogether impersonal toward her. To him, she seemed only to be a fellow-scientist. Yet Bill knew that the Prince was aware of the girl's feelings—and he suspected that the Prince was trying to stifle a growing reciprocal emotion of his own.
Bill spent long hours on the bridge with Captain Brand, staring out at the star-scattered midnight of space. The earth shrank quickly, until it was a tiny green disk, with the moon an almost invisible white speck beside it. Day by day, Mars grew larger. It swelled from an ocher point to a little red disk.