They reached the house a few minutes later, and went in the front door. The sounds of two voices came from the library. One of them was that of Professor Henderson. He was saying:

"I tell you it can't be done! It is utterly impossible! It is madness to think of such a terrible trip!"

"And I tell you it can be done--it shall be done and you are the very man to accomplish it," insisted the other. "You and your young a.s.sistants will succeed. I know you will. You will go with me, and we will make the longest journey on record."

CHAPTER IV

WONDERFUL PLAN

"I wonder what they can be talking about?" asked Mark of Jack, as they paused outside the library door.

"I don t know, but it concerns us."

"What makes you think so?"

"Because, didn't you hear the stranger speak of us as the 'young a.s.sistants'? That's us."

"Very likely. But who is the man in with Professor Henderson, and what is the wonderful journey he is talking about?"

"Dat gen'man in wid de perfesser am also a perfessor." Explained Washington in a whisper. "He's Perfesser Santell Roumann. Now I 'spects I'd better saggasiate mahself inter proximity t' de culinary reservation."

"You mean you've got to go to the kitchen?" asked Jack with a smile.

"Dat's what I approximated to yo'," replied the colored man.

"I wonder if we'd better go in now, or wait until Professor Henderson is through talking to Mr. Roumann?" asked Mark.

"Yo' am to go right in," remarked Washington. "Dem's de orders I got when I went t' de statione t' meet yo'."

"All right," a.s.sented Jack. "Come on, Mark. We'll find out what's wanted of us."

The two boys entered the library, whence the voices of Professor Henderson and Mr. Roumann could still be heard in earnest discussion. Mr. Henderson looked up as his proteges advanced to the middle of the apartment.

"Jack! Mark!" he exclaimed. "I am very glad you came so promptly. I have something very important to communicate to you--something that I hope will make up for the loss you suffer in being taken away from college in the middle of the term. Or, to be more correct, Mr. Roumann will impart most of the information, for it is at his suggestion that I sent for you."

"Are these the young a.s.sistants of whom you spoke?" asked the other man, and the boys noticed that he was a big, burly German, with a bushy, gray beard, and penetrating, blue eyes.

"This is Jack Darrow," said the professor, indicating the stout youth, "and the other is Mark Sampson. They have lived with me several years now, and we have had many adventures together."

"Ha! Hum! Yes!" murmured Mr. Roumann, then he said something in German.

"I beg your pardon," he went on quickly. "I have a habit of talking to myself in my own language once in a while. What I said was that I did not know the lads were so young. I am somewhat apprehensive--"

"Do not be alarmed on the score of their youth," cried Professor Henderson. "I a.s.sure you that they have had a peculiar training, and, in some scientific attainments, they know as much as I do.

You will not find them too young for our purpose, in case we decide that the thing can be done."

"I tell you it can be done, and it shall be done," insisted Mr.

Roumann.

"I have my doubts," went on Mr. Henderson.

Jack and Mark must have shown the wonder they felt at this talk between the professor and his friend, for their guardian turned to them and said:

"Boys, you must excuse me for not telling you at once the reason why I sent for you. The truth is that Mr. Roumann has laid a very strange proposition before me. It is so stupendous that I hardly know whether to consider it or not. I want to talk with you about it, and see what you think."

"They will go with us, will they not?" asked Mr. Roumann.

"That is for them to say," replied Mr. Henderson.

"Go where?" asked Jack, wondering if there was in prospect another voyage to one of the Poles, or a trip to the interior of the earth.

Professor Henderson looked at the other man. They were silent a moment.

"Shall I tell them?" asked Mr. Henderson.

"Surely," a.s.sented Mr. Roumann. "It all depends on you and them whether we go or remain on earth."

Jack started. Then there was a question of getting off the earth. He began to think there might be exciting times for Mark and himself.

"Mr. Roumann has proposed a wonderful plan to me," went on Professor Henderson. "It is nothing more nor less than a trip to--"

"Mars!" burst out the blue-eyed man. "We are going to make the most wonderful journey on record. A trip through s.p.a.ce to the planet Mars! Such an opportunity for reaching it, and proving whether or not there is life on it, will not occur again for many years. It is now but thirty-five millions of miles away from us.

Soon it will begin to recede, at the rate of twenty-eight millions of miles a year, until it is two hundred and thirty four millions of miles away from us. Then we may never be able to reach it. Now, when it is but thirty-five millions of miles away, we have a chance to get there."

"I still believe it is impossible," said Professor Henderson in a low voice.

"Nothing is impossible!" exclaimed Mr. Roumann. "We shall go to Mars! I say it! I who know! I who hold the secret of the wonderful power that will take us there, and, what is more, bring us back! I say it! We shall go!"

"Impossible!" said the professor again, shaking his head.

"Don't say that word!" implored Mr. Roumann. "I will prove to you that we shall go."

"Go to Mars!" exclaimed Mark.

"Thirty-five million miles!" exclaimed Jack with awe in his tones. "How can we ever cover that distance? No airship ever made would do it."

"Not an airship, perhaps," said Mr. Roumann, "but something else. I will tell you how--"

"Perhaps I had better explain from the beginning," interrupted Mr. Henderson.

"Maybe it will be better," a.s.sented the other.

"Boys, be seated," spoke their guardian, and Jack and Mark took chairs. "Mr. Santell Roumann is an inventor, like myself," went on Mr. Henderson. "I have known him for several years, but I had not seen him in a long time, until he called on me the other day with his strange proposition. We used to attend the same college, but since his graduation he has been experimenting in Germany."