"You came near getting blown off the track," remarked his companion, which was as near to a joke as he ever would come, for, though Jack was jolly and full of fun, Mark was more serious, inclined to take a sterner view of life.
"Oh, I'll succeed yet!" exclaimed Jack. "And when I do—you'll see something—that's all."
"And feel it, too," added Mark, putting his hand on his head, the book having raised quite a lump.
It was several days after this before the boys had the chance to work alone in the laboratory again, and Jack had to promise not to try his experiment with the new gas before this privilege was granted him.
"Want any help?" asked Dick Jenfer, another student, as he saw Jack and Mark enter the laboratory.
"Yes, if you want to hold a test tube for me," answered Jack. "I'm going to try a new way of making oxygen."
"No, thanks! Not for mine!" exclaimed Dick as he turned away. "I don't want to be around when you try your new experiments. The old way of making oxygen is good enough for me."
"Well, I have a new scheme," went on Jack.
Soon he and Mark, whom he had again induced to help him, were busy with test tubes, rubber hose, Bunsen flames, jars of water, and all that is required to make oxygen.
Somewhat to his own surprise, the experiment Jack tried was a success. He collected a jarful of oxygen, generated in a way he had thought out for himself. It was much simpler than the usual method.