Produced by Sean Pobuda THROUGH SPACE TO MARS Or the Longest Journey on Record By Roy Rockwood #4 in the "Great Marvel Series" CHAPTER I TWO CHUMS "Mark, hand me that test tube, will you, please?" The lad who had made the request looked over at his companion, a boy of about his own age, who was on the other side of the laboratory table. "The big one, or the small one?" questioned Mark Sampson. "The large one," answered Jack Darrow. "I want to put plenty of the chemical in this time and give it a good try." "Now be careful, Jack. You know what happened the last time." "You mean what nearly happened. The tube burst, but we didn't get hurt. I have to laugh when I think of the way you ducked under the table. Ha, ha! It was awfully funny!" "Humph! Maybe you think so, but I don't," responded Mark with rather a serious air. "I noticed that you got behind a chair." "Well, of course. I didn't want broken glass in my eyes. Come on, are you going to hand me that test tube, or will I have to come and get it? We haven't much more time to-day." "Oh, here's the tube," said Mark as he passed it over. "But please be careful, Jack." Jack measured out some black chemical that resembled gunpowder, and poured it into the test tube which Mark handed him. Then he inserted in the opening a cork, from which extended a glass tube, to the outer end of which was fastened a rubber pipe. He paused in his experiment to laugh again. "What are you making--laughing gas?" asked Mark. "No. But--excuse me--ha, ha! I can't help laughing when I think of the way you ducked under the table the other day." "Maybe you'll laugh on the other side of your countenance, as Washington White would say," commented Mark; "especially if that big tube bursts." "But it isn't going to burst." "How do you know?" "Well, I worked out this experiment carefully. I've calculated just how strong the new gas will be, and--" "Ah, that's just it. It's a new gas, and you've never yet succeeded in making it, have you?" "No; but--" "And it takes a different combination of chemicals to make it from any you ever experimented with before, doesn't it?" asked Mark. "It does. But--" "Yes, and I don't see how you can tell, with any amount of calculation, just how much force will develop from those chemicals, as no one ever put them together before." "Well, maybe I can't," admitted Jack. "But this tube is very strong, and even if it does break nothing very serious can happen." "Unless the gas you expect to generate is stronger than you have any idea of." "Well, I'm going to do it. I've got half an hour before Professor Lenton and his class comes in, and that's time enough. Here, just hold this rubber tube under this jar, will you? And be sure to keep the edge of the jar below the surface of the water. I don't want any of the gas to escape."