“Just wanted to see how you looked in action, Donnie,” Lansing said, explaining his own butt-in. “The fellows tell me you are a whale in Math. Where did you get it all?” “Oh, I don’t know,” said Larry. “I never did have much trouble with figures.” “You’re in luck. Freshman Math. is plenty stiff in Sheddon. I fell down all over it in my first year. I remember there was one problem――old ‘seven-fifty-four,’ we used to call it――that was a regular bear trap――caught the last man of us in my year.” “Seven-fifty-four?” Larry queried. “Why, we have that in to-morrow’s assignment. Here it is,” and from a sheaf of demonstration sheets he took one covered handsomely with figures and illustrative drawings. “That’s the old boy,” said Lansing, running his eye over the sheet; and from that he went on, talking easily of his Freshman days and their trials and tribulations. As Lansing talked, Larry was watching the clock rather anxiously, hoping Dick would come in. In his bones he felt that Lansing was waiting for a chance to say something about the coming bid for membership in the Omegs――possibly the bid itself would be made. And Larry was not yet ready with his answer. Ambition, a keen hunger and thirst to be one of the particularized, was pulling one way, and something else――he couldn’t quite give it a definite name――was nervously putting the brakes on. As it turned out, the clock-watching wasn’t needed. Dick came in before the room was cleared, so Larry had the excuse he had been waiting for; the chance to plead his _Micrometer_ assignment and get away to the gymnasium without leaving his drop-ins with no host. During the basket-ball practice games through which he sat making notes for Havercamp’s blue-pencilings, Problem 754, the one to which Lansing had called attention, was ambling around in the back part of his brain; and in the process of recalling it, step by step, it suddenly occurred to him that in a certain small particular the demonstration he had shown Lansing was at fault; the result was all right, but in one place the value of the _x_ plus _y_ had been assumed and not proved. “Queer how I came to make such a bonehead crack as that,” he muttered, as he walked back across the campus; and when he reached his room and found everybody gone, and Dick――for a wonder――in bed and sound asleep, he looked on the study table for the demonstration sheet, meaning to correct the slip. Oddly enough, the sheet wasn’t to be found. He had either misplaced it, or it had disappeared during his absence. Since it was wrong, anyhow, he did not search very long or carefully; instead, he sat down and painstakingly made another sheet, correcting the error that had appeared in the original; did that, and then went to bed and forgot the incident.