"I guess you would," responded Mr. Roumann. "Well, we'll take good care that you do not get loose again." The bonds of the maniac were made more secure, and Washington White was told to keep, close watch over him. It was the day after this occurrence, though Jack and Mark had not gotten over talking about it, that they were in the pilot house with Professor Henderson. The projectile was speeding along rapidly, and from calculations that had been made it was believed they would arrive at Mars in about two days. "I'll be glad of it," said Jack. "I want a chance to stretch my legs." "And grow lighter," added Mark. "You're fatter than ever since you began this trip." "That's because I don't have any exercise. But I'll make up for it. I understand that on Mars one can jump twice as far as he can on the earth, due to the less dense atmosphere." "Well, we'll soon see," said Mark. Mr. Henderson suddenly bent over one of the indicators. He pressed a lever, turned a wheel, and then exclaimed: "The Etherium motor has stopped working 'again! I wonder if the maniac is loose!" "We'll see!" cried Jack, as he and Mark hurried toward the engine-room. They found Mr. Roumann there. "The motor has stopped!" exclaimed Jack. "I know it." "Has there been an accident?" "No." "What's the matter, then?" "We have completed our journey through the ether. The motor will only work in that." "And that means--" began Mark. "That we have reached the atmosphere of Mars!" exclaimed Mr. Roumann in triumph. CHAPTER XXI MARS AT LAST Anticipating, as they had for some time past, such an announcement, it was none the less startling to the boys. "Then we are really nearing Mars?" exclaimed Jack. "Not only nearing it, but we will be there within twenty-four hours," answered the German scientist. "I was looking for this. I expected the Etherium motor to stop as soon as it reached the atmosphere of the planet, and it has done so. We will not have to start it again until we make the return trip. I will now again put into operation the atmospheric motor, and we will see how it behaves. Kindly inform Mr. Henderson, so he will understand what is taking place." Mark hastened to the pilot house with this message, and then returned to watch Mr. Roumann, the professor agreeing to remain at the steering wheel until relieved by his friend. Mr. Roumann began adjusting the second motor. It had been kept in readiness for instant service, and did not require much attention. "I don't see why we have to use it at all," said Jack. "Why shouldn't we?" Mark wanted to know. "Because if we are near Mars it ought to attract us, just as if we were near the earth. We ought to fall right into it."