There was a trembling to the great projectile. Up rose her sharp-pointed bow. She swayed slightly in the air. The trembling increased. The great Cardite motor hummed and throbbed. There was a crackling as from a wireless apparatus.

Then, with a rush and a roar, the big steel car, resembling an enormous cigar, soared away from the earth, like some gigantic piece of fireworks, and shot toward the sky.

"We're off!" shouted Mark.

"For the moon!" added Jack.

And the _Annihilator_ soared upward and onward, while those in her never dreamed of the fearful adventures that were to befall them ere they would again be headed toward the earth.

CHAPTER XV

THE SHANGHAI MAKES TROUBLE

Remaining in the engine room long enough to see that all the motors and apparatus were working smoothly, Professor Henderson made his way to the pilot house forward, where Mark and Jack were in charge of the steering gears. The projectile could be started and stopped from there, as well as from the engine room, once the motor was set going.

"Well, boys, how does it feel to be in s.p.a.ce once more?" asked the scientist.

"Fine," answered Mark. "But while I was shut up in that old house I feared I'd never have this chance again."

"It seems like old times again, to be flying through s.p.a.ce," remarked Jack. "My! but we aren't making half the speed of which the projectile is capable. Why, we're only going about twenty miles a second," and he spoke as if that was a mere nothing.

"Twenty miles is some speed," observed Mark.

"The earth goes around the sun at the rate of nineteen miles a second, or about seventy-five times as fast as the swiftest cannon-ball, so you see, Jack, you are 'going some,' as the boys say."

"Yes, but we went much faster when we went to Mars. Still, no matter how fast we travel, you'd never realize it inside here."

This was true. So well balanced was the projectile, and so delicately poised was the machinery, that the terrifically fast rate of travel, rivalling that of the earth, was no more noticed than we, on this globe, notice our pace of nineteen miles a second around the sun.

"Everything seems to be all right," observed Professor Henderson, as he looked out of the plate-gla.s.s window of the pilot house into a sea of rolling mist, which represented the ether, for they had soon pa.s.sed through the atmosphere of the earth, which scientists estimate to be two hundred miles in thickness.

"Are we going to move any faster than this?" asked Jack, who seemed possessed of a speed mania.

"Not right away," replied Mr. Henderson. "Professor Roumann wants to thoroughly test the Cardite motor first. Then, when he finds that it works all right, we may go faster. But we will be at the moon soon enough as it is. It is time we headed more directly on our proper way, though, so I think I will ask Mr. Roumann to step here and aid me in getting the projectile on the right course. You boys had better remain also and learn how it is done. You may need to know some time."

"I'll call the professor here, if he can leave the engine room," said Mark, and he found the German bending over some complicated apparatus.

The scientist announced that the machines would run themselves automatically for a while, so he accompanied the lad back to the pilot-house.

There, consulting big charts of the heavens, and by making some intricate calculations, which the boys partly understood, the German and Mr. Henderson were able to locate the exact position of the moon, though that body was not then in sight, being behind the earth.

"That ought to bring us there inside of a week," announced Mr.

Henderson, as he fastened the automatic steering apparatus in place.

"The projectile will now be held on a straight course, and I hope we shall not have to change it."

"Could anything cause us to swerve to one side?" asked Jack.

"Sure," replied Mark. "Don't you remember how, in the trip to Mars, we nearly collided with the comet? If we are in danger of hitting another one of those things, or even a meteor, we'll steer out of the way, won't we?"

"Of course. I forgot about that," admitted Jack.

"Yes," declared Professor Roumann, "we'll have to be on the lookout for wandering meteors or other stray heavenly bodies. But our instruments will give us timely warning of them. Now, I think we can leave the projectile to herself while I make sure that all the machinery is running smoothly. You boys may stay here if you like, though there isn't much to see."

There wasn't. It was totally unlike taking a trip on earth, where the ever-varying scenery makes a journey pleasant. There was no landscape to greet the eye now. It was even unlike a trip in a balloon, for in that sort of air-craft, at least for a time, a glimpse of the earth can be had. Now there was nothing but a white blanket of mist to be seen, which rolled this way and that. Occasionally it was dispelled, and the full, golden sunlight bathed the projectile. The earth had long since dropped out of sight, for it required only a few seconds to put the _Annihilator_ high up in a position where even the most intrepid balloonist had never ventured.

Mark and Jack sat for a few minutes in the pilot-house, looking out into the ether. But they soon tired of seeing absolutely nothing.

"I wonder what we'll do when we get to the moon?" asked Jack of his chum.

"Why, I suppose you'll make a dive for a hatful of diamonds, won't you?

That is, if you still believe that Martian newspaper account."

"I sure do."

The boys found the two professors busy adjusting some of the delicate scientific instruments with which they expected to make observations on the trip, and after they reached the moon.

"What is your opinion, Professor Roumann, of the temperature at the moon's surface?" asked Mr. Henderson.

"I am in two minds about it," was the reply. "A few years ago, I see by an astronomy, Lord Rosse inferred from his observations that the temperature rose at its maximum (or about three days after full moon) far above that of boiling water."

"Boiling water!" e.j.a.c.u.l.a.t.ed Mark. "Wow! That won't be very nice. I don't want to be boiled like a lobster!"

"Wait a moment," cautioned Mr. Roumann, with a smile. "Later, Lord Rosse's own investigations, and those of Langley, threw some doubts on this. There is said to be no air blanket about the moon, as there is about the earth, so that the moon loses heat as fast as it receives it; and it now seems more probable that the temperature never rises above the freezing point of water, just as is the case on our highest mountains."

"That's better," came from Jack. "We can stand a low temperature more easily than we can to be boiled; eh, Jack?"

"Sure. But I don't want to be frozen or boiled either, if I can help it. Guess I'll wear my fur suit that we brought back from the North Pole with us."

"I agree with you, Professor Roumann, about the temperature," announced Mr. Henderson, "so we must make up our minds to shiver, rather than melt. But we are prepared for that."

"What about there being no air on the moon?" asked Jack.

"Oh, we can manufacture our own oxygen," said Mark. "We can walk around with an air tank on our shoulders, as we did when we went beneath the surface of the ocean. Now, I guess----"

"Dinner am served in de dining car!" interrupted Washington White, his black face grinning cheerfully. He used to be a waiter in a Pullman, and he was proud of it. "First call fo' dinner!" he went on. "Part ob it am boiled, part am roasted, laik I done heah yo' talkin' 'bout jest now, an' part am frozed--dat's de ice cream," he added hastily, lest there be a mistake about it.

"Well, that sounds good," observed Mark. "Come on, everybody," and he led the way to the dining cabin.

They had not been at the table more than a few minutes, and had begun on the "boiled" part of the meal, which was the soup, when from the engine room there came a curious, whining noise, as when an electric motor slows up.

"What's that?" cried Professor Henderson, jumping up from his seat in alarm.

"Something wrong in the engine room," cried Mr. Roumann.

The two scientists, followed by the boys, hurried to where the various pieces of apparatus were sending the projectile forward through s.p.a.ce.

Already there was an appreciable slackening of speed.