"Keep shady," muttered Jack. "Some of the teachers have rooms near here." They walked along under the shadow of the Hall until they came to a window from which a brilliant light streamed forth. It came from a crack between the lowered shade and the casement. It was impossible to pass it without seeing what was going on inside the apartment. At the same time they could hear the murmur of voices. "Adrian Bagot, and his two cronies up to some trick!" whispered Jack, as he grasped Sam by the arm. The two friends saw the three new students bending over a table, containing a pot of something, which they seemed to be stirring with a long stick. "What are they up to?" whispered Sam. "Experimenting with chemicals, perhaps," said Jack. "Don't you believe it," retorted Sam. "They're up to some game, you can bet. I wonder if we can't get wise to what it is." Cautiously they drew nearer to the window. They found it was open a crack. "Will it make much of an explosion?" asked Ed Simpson. "Hardly any," replied Higley. "Only a puff and lots of smoke, but it will leave its mark all right, and I guess those fresh friends of Jack Ranger's will laugh on the other corner of their mouths." "I'd like to get even with them before the term closes," put in Adrian. "We'll do it all right," went on Ed. "Don't be too sure of that," whispered Jack. It did not require much effort on the part of Jack and Sam to understand what the three conspirators were up to. Their conversation, which floated through the opened window, and their references to certain localities put the two listeners in possession of the whole scheme. "Well, if that isn't the limit," said Jack in a whisper. "I wouldn't believe they'd dare to do it." "How can we foil their plans?" asked Sam. "Hark, some one is coming," said Jack, dropping down on his hands and knees, an example which Sam followed. Then came a cautious signal, a whistle. "It's John Smith, my Indian friend!" exclaimed Jack. "He must have just got back," for the half-breed had been away for a few weeks, as one of his relatives was ill. Jack sounded a cautious whistle in reply, and soon the Indian student was at his side. There were hurried greetings, and Jack soon explained the situation. "Let me think it over a minute," said John Smith. "It takes me rather suddenly." For a few seconds John remained in deep thought. Then he exclaimed: "I think I have it. Have you any chemicals in your room, Jack?" "Plenty," was the answer. "I've been boning on that lately, and I got a fresh supply from the laboratory the other day to experiment with." "Then I think we'll make these chaps open their eyes." The three friends hurried to Jack's room, where they were busy for some time, behind carefully drawn shades. At the end of about two hours, Jack, who had been keeping watch from a window, exclaimed: "There they go with the stuff. It's time we got a move on."