"But there isn't anything to see," objected Andy. "Now, I like scenery when I travel." "Well, it's something to always be in sight of the sun," put in Mark. "Yes, and when we get to Mars there'll be plenty to look at," suggested Jack. "We can see the rings around it." "Mars hasn't any rings around it," retorted Mark, who had a good memory for scientific facts. "That's Saturn you're thinking of." "Oh, yes, so it is. But hasn't Mars got a lot of moons, or something like that? Seems to me I've heard about 'em." "Mars has two moons, or satellites," stated Mr. Roumann, who had studied much about the red planet, "but they do not amount to much, compared to our moon. One is about ten thousand miles from Mars, and is called Deimos, and the other, which is but sixteen hundred miles from the planet, is called Phobos by astronomers." "And how far away is our moon from the earth?" asked Mark. "It varies from about two hundred and fifty-two thousand miles to two hundred and twenty-one thousand miles." "Then I should think the people on Mars would get more light from their two moons, so much closer to them, than we do from our moon, so far off," remarked Jack. "No, they don't, at least as far as we know. The one closest to them gives about one-sixtieth of our moonlight, and the outer one about one twelve-hundredth, so you see that's not much. A peculiar feature of the inner moon is that it makes a revolution about Mars in seven hours, or more than three times in a day, and it rises in the west and sets in the east, while the moon farthest away from the planet rises just as our moon does, in the east, but it comes up only once in about five days." "Golly!" exclaimed Washington, who had been listening. "Dat suah am a funny place. Two little moons, one shootin' around you three times a day, an' de odder one circlin' around once in five days! Land a' massy! I'll git all turned around up dere!" "Yes, you'll have to be careful, Wash," cautioned Jack. "If you go out for a moonlight walk you may have to come home in the dark." "Den I ain't goin'; an' when I do I'll take a lantern." Mr. Roumann told the boys much more of interest about Mars, and then, taking them to the engine-room, he showed them something about adjusting the motors and other machinery, though he did not disclose the secret of the power. "Now we'll go to the pilot house, and I'll show you some things there," he concluded. They found Professor Henderson at the wheel. "Is everything all right?" asked the German. "I think so," answered the scientist. "This airship doesn't behave exactly as the ones I constructed before, but it seems to be moving along at good speed." "Yes, we have increased our rate of progress," stated Mr. Roumann. "We are now going nearly fifty-five miles a second. At that rate we shall be beyond the atmosphere sooner than I expected."