It took some little time to adjust the machinery, and then the travelers took from their supplies some personal belongings, which they wished to have with them.

"Now to see to that crazy machinist," said Mr. Henderson, when they were ready to leave the projectile again. "I wish we could get rid of him. He's a nuisance."

They went to the storeroom, where he had been confined, but the man was not there.

"He's hiding again," declared Jack.

"No; he's got away!" exclaimed Mr. Roumann. "See, the ropes with which we bound him have been broken. When the Martians came out to feed him last night they could not have fastened them securely. Well, he's gone, and I don't know but what I'm glad of it."

But there came a time when they were all very sorry that the insane man had escaped, for he caused them much trouble.

As they left the projectile to go to the house provided for them in Martopolis, Mr. Roumann took with him several small iron boxes.

"What are those for?" asked Jack.

"To put that red stuff in," replied the scientist.

"I am going to make another try for some, but I'll take a different road this time."

For a week or more the travelers lived in their house in Martopolis. They were courteously treated by the Martians, and soon began to pick up the language, which was very simple when once the principles of it were understood.

Several times the travelers were taken before the Great Council, as it was called, and asked in regard to matters on the world they had left. In turn the adventurers learned much about Mars.

Though it was much smaller than our earth, it was superior to it in many ways. One was the simplicity of life. The Martians never had any need of clothes, for they were born with fur and feathers, which were renewed by Nature from time to time. They had to contend with a large quant.i.ty of water, which covered most of the surface of their planet, but by ingenious means they got along nearly as well as if there was more land. In science they were far ahead of scientists of the earth, and they were fortunate in possessing the red substance, which they called Cardite, and which was their only source of light, heat and power. With it they accomplished much that the world-dwellers have to bring about by great labor.

By inquiry, after they had learned the language, the travelers found out that Cardite was regarded with much reverence, and there was a tradition that if any of it was taken away from Mars, the planet would disappear.

"No wonder they didn't want us to get any," said Mr. Roumann.

"But I'm going to have some, for all that. It's all nonsense to think any harm can come from taking it. It will not injure their planet, and it will be a fortune to us. They must have a lot of it, for they told us that all the cities on Mars, and there are several of them, are lighted and heated by it."

"But how are you going to get it." asked Mark.

"By going a different route. I'm going to get a boat, and go by water. I've found out how to run one of their boats by means of the red substance, and some day we'll sail over the lake to the hills and get some Cardite."

They waited another week, and, as they found less and less attention was paid to them from day to day, they decided to make an attempt to get some of the treasure.

They started one morning in a large boat, which Silex Corundum, the ruler of Mars, had placed at their disposal, and in a short time were approaching the distant hills, at the foot of which was the great lake. The boat moved swiftly, the controlling mechanism consisting of three little k.n.o.bs on the outside of the box containing the Cardite. One sent the craft forward, one reversed it, and the other stopped it.

"We're almost there," said Mr. Roumann, after about an hour's sail. "There are no guards this way, just as I hoped. We shall soon be enormously wealthy."

Nearer and nearer came the boat to the hills. When they were within a half mile of them Jack, who was in the bow, uttered a cry.

"A whirlpool! A whirlpool!" he shouted. "We're heading right into it!"

Mr. Roumann, who was steering, tried to turn the boat to one side, but the craft would not answer the helm.

"Shut off the power and reverse!" exclaimed Mr. Henderson, when he saw that the boat was still rushing into the dangerous swirl of water.

Mark, who was near the metal box, did so. But even the power of Cardite was of no avail against the awful suction of the whirlpool. The boat began to go around in a great circle, ever coming nearer and nearer to the black, swirling center.

"No wonder they needed no guards on the water side," gloomily observed Mr. Roumann as he stood up and looked at the hills.

"The whirlpool is the best protector they could have."

In deadly peril, the adventurers watched their boat coming nearer and nearer to the terrible center of the angry waters.

CHAPTER XXVII

GETTING THE CARDITE

"Isn't there any way of escape?" asked Jack in a low voice, as he crouched in the bow and peered into the whirlpool, on the edge of which they were circling.

"I don't see any," replied Mr. Roumann. "I am very sorry I got you into this trouble. If I had not insisted on coming for the red substance we would not be in this danger."

"It's as much our fault as yours," declared the professor. "We were anxious to get some of the treasure also."

"And now none of us will have any use for it," observed Andy dryly. "When we slide down into that hole it will be all up with us."

They all shuddered as they saw the black hole, around which the waters raced in a circle.

"I wonder what's down there?" asked Mark.

"It isn't a good thing to think about," responded Jack. "I always was afraid of whirlpools."

The boat was now beginning to go around faster. The occupants were getting dizzy with the motion. They could hear a distant roar, and knew that it came from the water falling down some great depth, into which they seemed fated to be dashed.

"Did you turn on all the power of the boat?" asked Jack after a period of silence. "Seems to me we didn't come along very fast in this craft. The one we were in first went at a great rate.

Maybe we don't understand how to make it go at top speed."

"I turned the k.n.o.bs every way I could think of," replied Mr.

Roumann. "But it would take terrific speed and power to free us from the suction of the whirlpool."

Jack moved back to the stern, where the box was, containing the red substance that furnished power to move the boat. He looked closely at it.

Meanwhile the boat was moving around in ever-narrowing circles, faster and faster. Jack noticed that twice in each revolution it went respectively lower and higher on the course, and always at the same places. That is to say, the whirlpool was on what might be termed a slant. At one time the boat would be at the lowest point, and at another at the highest point. At the low point the occupants of the craft were out of sight of everything, as when a ship is in the hollow of the sea. A little later they would be raised up on a crest of water so that they could look to the distant hills.

"If we could only get power enough to shoot the boat out at an angle when it gets to the high point, we could escape," thought Jack.

But how could he obtain this power? The mechanism seemed to be working at the greatest force, for, after an attempt had been made to stay the progress of the boat by reversing it, Mr.

Roumann had again put on full speed ahead.

But was it full speed? That was what Jack wanted to know.

He examined every inch of the box. At first he saw nothing but the three k.n.o.bs that had been used. Then, all at once, down underneath, he saw a small pin. It looked as if it could be moved. He took hold of it.

"I wonder what will happen if I pull it out or push it in?" he asked himself. Then he happened to remember that in an electric battery, to obtain more power, you must pull out a certain pin.