Andy and Dunk, who had jumped up and come to the door of their room on hearing Frank’s explanation, stood looking at him for a second, rather startled by his news. Then Andy, realizing that this might be a chance to discover who had been carrying on the mysterious quadrangle robberies, exclaimed:

“Come on down this way! The hall ends just around the corner and there’s no way out. It’s a blind alley, and if the fellow went down here we sure have him!”

“Good for you!” cried Dunk. “Wait until we get something to tackle him with in case he fights.”

“That’s so,” said Andy. “Here, I’ll take our poker, and you can have the fire tongs, Dunk.”

From a brass stand near the fireplace Andy caught up the articles he mentioned.

“Where’s something for me?” asked Frank.

“Here, take the shovel,” spoke Dunk passing it over. “Say, what sort of a fellow was it you saw run out of your room?”

“I didn’t have much chance to notice, he went so like a flash.”

“Was it—er—one of our fellows—I mean a college man—did he look like that?” asked Andy. He was conscious of the fact that he had rather stammered over this. Truth to tell, he feared lest Link might have yielded to temptation. Since the episode of Dunk’s watch Andy had been doing some hard thinking.

“Well, the fellow did look like a college chap,” admitted Frank, “but of course it couldn’t be. No Yale man would be guilty of a thing like that.”

“Of course not!” agreed Dunk. “But say, if we’re going to make a capture we’d better get busy. Are you sure there’s no way out from this corridor, Andy?”

“Sure not. It ends blank. The fellow is surely trapped.”

They hurried out into the corridor, and started down it, armed with the fire irons. Though they had talked rather loudly, and were under considerable excitement, no attention had been attracted to them. Most of the rooms on that floor were not occupied just then, and if there were students in the others they did not come out to see what was taking place.

“Say, it would be great if we could capture the thief!” said Dunk.

“Yes, and end the quadrangle mystery,” added Andy.

“I don’t care so much about ending the mystery as I do about getting back my tennis cup and the book,” spoke Frank.

“What sort of a book was it?” Andy inquired.

“A reference work on inorganic chemistry,” answered Frank. “Cost me ten plunks, too. I can’t afford to lose it for I need it in my work.”

“Some book!” murmured Andy, as the three hastened on.

They tried door after door as they passed, but most of them were locked. One or two opened to disclose students dressing or shaving, and to the rather indignant inquiries as to what was wanted, Dunk would exclaim hastily:

“Oh, we are looking for a fellow—that’s all.”

“Hazing?” sometimes would be inquired.

“Sort of,” Dunk would answer. “No use telling ’em what it is until we’ve got something to show,” he added to his companions. They agreed with him.

They had now reached the turn of corridor where a short passage, making an L, branched off. So far they had seen no trace of the thief.

“There’s a big closet, or storeroom, at the end,” explained Andy. “The fellow may be hiding in there.”

An examination of the few rooms remaining on this short turn of the passage did not disclose the youth they sought. All of the doors were locked.

“He may be hiding in one of them,” suggested Dunk.

“If he is all we’ll have to do will be to wait down at the other end, if we don’t find him in the store room,” spoke Andy. “He’ll have to come out some time, and it’s too high up for him to jump.”

“It’s queer we didn’t hear him run past our room,” remarked Dunk.

“He had on rubber shoes—that’s why,” explained Frank. “He went out of my room like a shadow. At first I didn’t realize what it was, but when I found my stuff had vanished I woke up.”

“Rubber shoes, eh?” said Andy. “He’s an up-to-date burglar all right.”

“Well, let’s try the storeroom,” suggested Dunk, as they neared it. They were rather nervous, in spite of the fact that their forces outnumbered the enemy three to one. With shovel, tongs and poker held in readiness, they advanced. The door of the big closet was closed, and, just as Andy was about to put his hand on the knob, the portal swung open, and out stepped—Mortimer Gaffington.

“Why—er—why—you—you——!” stammered Andy.

“Did you—have you——?” This was what Dunk tried to say.

“Is he in there?” Frank wanted to know.

Mortimer looked coolly at the three.

“I say,” he drawled, “what’s up? Are you looking for a rat?”

“No, the quadrangle thief!” exclaimed Andy. “He went in Frank’s room and took his book and silver cup, and lit out. Came down here and we’re after him! Have you seen him?”

“No,” replied Mortimer, slowly. “I came up here to get Charley Taylor’s mushroom bat. He said he stuck it in here when the season was over, and he told me I could have it if I could fish it out. I had the dickens of a time in there, pawing over a lot of old stuff.”

“Did you get the bat?” asked Dunk.

“No. I don’t believe it’s there. If it is I’d have to haul everything out to get at it. I’m going to give it up.”

As he spoke he threw open the closet door. An electric light was burning inside, and there was revealed to the eyes of Andy and his chums a confused mass of material. Most of it was of a sporting character, and belonged to the students on that floor, they using the store room for the accumulation that could not be crowded into their own apartments.

“A regular junk heap,” commented Frank. “But where the mischief did that fellow go who was in my room?”

“It is sort of queer,” admitted Andy, as he looked down. Without intending to do so he noticed that Mortimer did not wear rubber-soled shoes, but had on a heavy pair that would have made noise enough down the corridor had he hurried along the passage.

“Maybe you dreamed it,” suggested Mortimer. “I didn’t see anything of anyone coming down here, and I was in that closet some time, rummaging away.”

“Must have been pretty warm in there—with the door closed,” suggested Dunk.

“It was hot. The door swung shut when I was away back in a corner trying to fish out that bat, and I didn’t want to climb back and open it. Well, I guess I’ll go clean up. I’m all dust.”

Truth to tell, he was rather disheveled, his clothes being spotted in several places with dust and cobwebs, while his face and hands were also soiled.

“Well, I guess he fooled us,” commented Andy. “I can’t understand it, though. We came down this hall right after him, and there’s no stairway going up or down from this end. How could he give us the slip?”

“Easily enough,” said Mortimer. “He could have slid into some empty room, locked the door on the inside and waited until you fellows rushed past. Then he could come out and go down the stairs behind you without you seeing him.”

“That’s what he did then, all right,” decided Dunk. “We might as well give it up. Report your loss, Frank.”

“Yes, I will. Whew! Another quadrangle robbery to add to the list. I wonder when this thing will stop?”

No one could answer him. Mortimer switched off the light in the store room, remarking that he’d have another look for the bat later. Then he accompanied Andy and the others on their way back down the corridor. Gaffington departed to his own dormitory, while Frank went to report to the Dean, and Andy and Dunk turned into their room.

“Well, what do you think of it?” asked Andy.

“I don’t know,” responded his roommate. “Mortimer’s explanation seems to cover it.”

“All the same we’ll leave our door open, on the chance that the thief may still be hiding in some empty room, and will try to sneak out,” suggested Andy.

“Sure, that’s good enough.”

But, though they watched for some time, no one came down the corridor past their room but the regular students.

And so the theft of the book and silver cup passed into history with the other mysteries. Further search was made, and the private detective agency, that had been engaged by the Dean, sent some active men scouting around, but nothing came of it.

The Christmas vacation was at hand and Andy went home to spend it in Dunmore. Chet, Ben and his other school chums were on hand, and as Andy remarked concerning the occasion, “a jolly time was had by all.”

Chet and Ben were with Andy most of the time, and when Andy told of the doings at Yale, Chet responded with an account of the fun at Harvard, while Ben related the doings of the Jersey Tiger.

Andy’s second term at Yale began early in the new year, and he arrived in New Haven during a driving snow storm. He went at once to his room, where he found a note from Dunk, who had come in shortly before.

“Come over to the eating joint,” the missive read, and Andy, stowing away his bag, headed for the place.

“Over in here!”

“Shove in, plenty of room!”

“Oh, you, Andy Blair!”

“Happy New Year!”

Thus was he greeted and thus he greeted in turn. Then, amid laughter and talk, and the rattle of knives and forks, acquaintanceship and friendship were renewed. Andy was beginning to feel like a seasoned Yale man now.

The studies of the second term were of increasing difficulty, and Andy and Dunk found they had to buckle down to steady work. But they had counted on this.

Still they found time for fun and jollity and spent many a pleasant evening in company with their other friends. Once or twice Mortimer and his cronies tried to get Dunk to spend the night with them, but he refused; or, if he did go, he took Andy with him, and the two always came home early, and with clear heads.

“They’re a pair of quitters!” said Len Scott, in disgust, after one occasion of this kind. “What do you want to bother with ’em for, Mort?”

“That’s what I say,” added Clarence Boyle.

“Oh, well, I may have my reasons,” returned Mortimer, loftily. “Dunk would be a good sort if he wasn’t tied fast to Andy. I can’t get along with him, though.”

“Me either,” added Len. “He’s too goody-goody.” Which was somewhat unjust to Andy.

The winter slowly wore on. Now and then there would be another of the mysterious robberies, and on nearly every occasion the article taken was of considerable value—jewelry, sporting trophies or expensive books. There was suspicion of many persons, but not enough to warrant an arrest.

One day Hal Pulter, who roomed in Wright Hall, near Dunk and Andy, reported that an expensive reference book had been taken from his room. The usual experience followed, with no result.

Then, about a week later, as Andy was walking past the small building at High and Elm streets, where the University Press had its quarters, he came up behind Mortimer Gaffington, who seemed to be studying a book.

Andy wondered somewhat at Mortimer’s application, particularly as it was snowing at the time. This enabled Andy to come close up behind Gaffington without the latter being aware of it, and, looking over the shoulder of the youth, Andy saw on the fly-leaf of the volume a peculiar ink blot.

At once a flash of recollection came to Andy. Well did he know that ink blot, for he had made it himself.

“Why, that’s Pulter’s book!” he exclaimed, speaking aloud involuntarily. “Where did you get it?”

Mortimer turned quickly and faced Andy.

“What’s that?” he asked, sharply.

“I say that’s Pulter’s book,” Andy went on.

“How do you know?” asked Mortimer.

“Why, by that big ink blot. I made it. Pulter was in our room with the book just before it was stolen, and my fountain pen leaked on it. That sure is Pulter’s book. Where did you get it? That’s the one he made such a fuss about!”