Mr. Salmon, who was the house-master over that section of Deepwater College in which the chums led a more or less care-free existence, was the best of good sorts, but hopeless as a disciplinarian. To begin with, he was partly deaf, and disrespectful juniors took advantage of the weakness in season and out of season. His own form, the sixth, to which all four of the Study 9 boys belonged, also contrived to have an easy time of it while he was in charge. So that if he observed a certain uneasiness on the part of the sharers of the Black Star secret, he might have ascribed it to post-holiday skittishness—at any rate, he said nothing about it, and the four of them hastened into conference immediately studies were over, and lent ear to the wise sayings of the eccentric genius, Septimus Patch.
"To begin with," said Patch, in his best Dear-Watson manner, "there's precious little beyond these footprints, in the shape of clues, but to a trained eye like mine those slight, almost meaningless marks have a story to tell. They are to me as an open book, and—"
"Cut out the cackle," said Jack Symonds brusquely, "and return to the washing. Get on with it."
"Examine this footprint closely," invited Patch, "and tell me what you see."
"A footprint, of course," said Jack. "In other words, a depression in the earth, caused by the yielding of the soil under a boot, which causes it to assume the shape—"
"Ass!" said Septimus cuttingly. "I mean, do you observe anything peculiar about it?"
"No. Why?"
"You see that snake-like mark across the place where the sole has rested?"
"We're not blind, professor. What of it?"
"Well, that's where the bootlace was stamped into the earth under the foot. You see that! Now, that means that the fellow had his boot unlaced."
"Marvellous!" exclaimed Jack. "How do you do it?" he added, peering anxiously at Patch. "Are you quite sure that you have come to no harm? The severe mental effort—"
"Cut the joking a moment. The man's boots were unlaced. What was the reason for that? Is it likely that a man who was planning a burglary would come in with unlaced boots? The thing is absurd. There are no houses within miles of this place, and if the fellow had been hiding in the bush, he would scarcely have had his boots unlaced. No; the deduction from that lace is that the chap belonged to the school."
"Yes, that sounds pretty right. You mean, he put on his boots to give the impression that he'd come from outside, but as he'd just slipped them on, he didn't lace them up, meaning to take them off again shortly afterwards."
"That's just it, comrade. Also, he was probably carrying them in his hand and getting around the corridors in stockinged feet. I think we've just about narrowed the search down to the school."
"Yes;" broke in Billy Faraday, who had been listening to the discussion with deep interest, "that's all right, but it's absurd to imagine that anyone from the Coll. had a hand in this affair. Fane says that the chap was a big fellow—"
"There wasn't much light," said Fane, "and I didn't see him for more than half a minute. All the same, he looked big. There was a scarf over the bottom of his face, of course, so I couldn't tell him that way."
"We've got no chance of finding out who he is, then," said Billy. "Even if it was one of the chaps, which is hard to believe. I had an idea that it was the bag-snatcher in the train, but he was quite short."
"Wait just a minute," interrupted Patch. "You want to hear all the detective's got to say, and then you can back-chat each other all day if you want to. I say we can find out who that chap was, and merely by this footprint again."
"Spit it out," invited Jack.
"Well, you can see the mark of the metal tag of that lace, can't you? And you will observe that it's broken in half. The jagged edge has left an unmistakable impression—see it? Just a minute."
He bent down, took a knife from his pocket, and detached a tiny square of the mud with the impression of the broken tag in it. This he held in the palm of his hand, and continued. "All we've got to do now is to find who owns the pair of boots that'd make an impression like this. There can't be any mistake, and it shouldn't take us long to run through all the boots in the school."
"When?"
"To-night, when they're downstairs for cleaning. They are brought back by the boy about half-past five—if we get down to-night we'd be able to examine them safely."
"Good on you," said Jack, slapping Septimus on the back with heartiness. "I didn't think you could do it, but it's a good notion all the same. By George, we ought to be able to find out who it is!"
"But—who could it be?" asked Billy, a furrow of puzzlement showing itself on his forehead. "That's what gets me! I can't imagine—"
"The bootlace will show—don't worry," said Septimus. "We can't do anything until we find that."
The four of them were wondering, as they sat in class that afternoon, who the intruder could be, and they looked at their class-mates with suspicious eyes. Big Martin, on account of his size, came in for furtive glances, but it was manifestly absurd that he could have been the culprit.
At this early stage of the term, nobody felt much like work, particularly Septimus Patch, who always contrived to be doing as much of his own private business as possible, and never paid much attention to the lesson in hand. Just at this moment he had arranged a big barrier of books all along the front of his desk, and, concealed behind the screen, he was tinkering with a weir-looking model of many springs, screws, and cogwheels.
Consequently he did not notice that the boy in front of him had been surreptitiously unlacing his boots. His first intimation that something was amiss was when he felt a sharp tug at his feet, and both his boots came off. He gasped with horror, and, peering over his barricade, observed that his two boots were travelling the round of the class, in different directions. His loud socks, of purplish and yellow colour-scheme, brought a snigger from the class. He wriggled, protesting.
"Patch!" It was the voice of Mr. Salmon, who was all unconscious of the diversion, but who saw Patch's movement. "Are you paying attention?"
"Yes, sir," mumbled Patch, reddening, and glaring, through his great horn-rimmed glasses, at his companions. "Back here with the giddy old boots, you asses!" he whispered, in a furious aside.
"Well, then," said Mr. Salmon, arranging his spectacles so that he could get a good view of the boy, "we were talking about Charles XII. Patch, tell me why he was unsuccessful against Peter in this campaign."
"You said, sir?" replied Patch.
"Why was he unsuccessful?"
"Ah, why?" said Patch, innocently.
"I don't believe you've been paying any attention whatever." The master ran round the class with a rapid cross-fire of questions, but the answers were unsatisfactory. He frowned, and coughed. "Here, Patch, you come out and read the account aloud," he commanded.
"Here, back with those boots," said Patch, frantically. But the boots had arrived at the other end of the room, and seemed likely to remain there.
"Do you hear me, boy?" demanded Mr. Salmon. "Come out at once. I never saw such indolence!"
With a groan Patch got up, and, amid the chuckles of the class, stepped forward to the dais where Mr. Salmon stood. But he had barely set foot on the stage, when he began a series of extraordinary antics.
"Ouch!" he howled, leaping four feet in the air, and bouncing with a thud. He danced about the dais on one foot, upsetting globes and maps, and tipping over one of the front desks upon its unfortunate occupant. "Take it out—take it out!"
"Ha, ha, ha!" roared the class, both at the wild leaps of Patch and the astounded horror of Mr. Salmon.
"Boy, boy!" cried the latter, "have you gone mad? Stop this at once—stop it, I say! Really I—!"
"Yow! It's sticking into me—quick! My foot—it's sharp!"
"His foot's sharp?" queried Mr. Salmon. "Patch—calm yourself, my poor fellow," he went on, imagining that, if Patch had really gone off his head, it would be safer to keep him calm.
"You are quite all right—you really are. Just keep calm, and the effects will—"
"Ha, ha, ha!" The class was convulsed, and rocked with merriment as Septimus Patch was seen to sit down on the floor and painfully extract a drawing-tack from his stockinged foot. The tack had been lying harmlessly on the dais, and Patch had planted his foot fairly upon it. Mr. Salmon adjusted his spectacles, and took in the amazing sight. The vivid colours of Patch's hose met his eye, and he gasped.
"Boy! What do you mean by this? Where are your boots?"
"Ah, where?" said Patch dreamily.
Mr. Salmon coloured deeply. "You are insolent—you will be punished," he affirmed. "Explain at once. Where have you put your boots?"
Squinting over the tops of his goggles, Patch descried his boots in place underneath his desk, standing demurely side by side as if nothing had ever been amiss with them.
"You will forgive me, comrade," he said, in his most buttery tones, "but I had to take them off. My feet got very hot."
"Your feet got hot?"
"Yes—just a physical weakness of mine. Whenever it occurs I simply have to take my boots off. I can't bear them."
"So you are hot-footed as well as hot-headed!" said Mr. Salmon.
The class simply roared. They kicked their feet, and rattled rulers on the desk. They always made a stupendous row whenever Mr. Salmon cracked one of his very mild jokes, and the genial house-master was so very deaf that the din came to his ears in the form of a loud titter, which had always pleased him greatly. The noise they made now could be heard a couple of corridors away, but Mr. Salmon nodded and smiled, satisfied with the reception of his sally.
"Go back to your seat, boy," he said, restored to good humour once more. "If your feet feel warm, it is doubtless because you wear such very hot socks."
At this remark there was a repetition of the hideous row; and Patch strolled back to his seat and his model-making without the slightest concern.
After "lights-out" that night the four pals got out of their dormitory, and in slippers made their way down to the boot-room, where they tumbled around among boots and blacking and brushes, before Patch applied a light to a fragment of candle that shed a flickering illumination over the rows of neatly cleaned boots.
"Now for it," said Billy Faraday, and without any more ado they set to work to examine the great stack of boots. It was fully half an hour before they had run through the pile, and then they had drawn a blank.
"It's no go," said Jack Symonds. "How now, professor?"
"The other House," said Patch calmly.
"What—Cooper's?"
"Of course," said Septimus. "Forward, comrades all!"
They crossed the quadrangle and the playing-fields to the other house of Deepwater College—Cooper's House.
"You were here last term, of course," said Jack Symonds to Patch. "You know your way about?"
"Rather, comrade; like the palm of my hand. Give us a leg up through this window."
Jack obliged him with a shove that nearly sent the investigator on to his head in the passageway beyond. In a little while the four had gained the boot-room, and there a much more cautious examination took place—more cautious because, if Cooper's masters or boys discovered them by any chance, then things would go hard with the intruders.
Inside of an hour the detectives had satisfied themselves that the boots had not been worn by any of the boys of Deepwater College.
"You've drawn another blank, Patchy," said Billy Faraday. "How do you account for this?"
"Account for it?" asked Patch, in wonderment. "What do you mean? This only brings us closer to our solution, as the great Holmes said—"
"Which Holmes? Oliver Wendell?" inquired Jack, with an air of acute interest.
"Sherlock Holmes, of course," returned Patch, with scorn. "I forgot that you are unfamiliar with the classics. Well, he laid it down as an axiom, once, that when you have disproved all but one of a number of solutions, that solution must be the correct one, no matter how absurd it seems."
"I get you. But how does it apply?"
"Why, if it wasn't one of the boys here, it must have been one of the masters that made the footprint."
"But what master would come at that game?" asked Billy incredulously. "Think it was old Salmon?"
"By the Great Moa!" exclaimed Jack in a loud tone, which called rebukes from his companions.
"Cut the shindy," advised Patch tersely, "or you'll have the whole House down on us. What's stung you?"
"Doctor Daw!" whispered Jack. "What about him?"
"Is he in his right mind?" asked Patch anxiously. "And who may Doctor Daw be? I've heard of his daughter, Marjory, but that was in my nursery-rhyme days. Expound."
In low tones, and as briefly as possible, Jack explained the strange connection which he suspected between Doctor Daw, the new master, and Tiger, the man who had run off with Billy's bag.
"What could be more likely," he said, "but that the two are in league with one another, and associates of old Lazare what's-his-name? Why didn't I think of it before?"
"This is important," said Patch, seriously. "Daw is a big man, and it might well have been him. Now, the only thing to do is to compare his bootlaces with that impression we've got. And how are we to do that?"
"Sneak up into his room and take a look at them," said Jack.
"Who's going, though? Four of us can't do it."
"Draw lots, then. Here, wait a minute till I collect some pieces of grass."
Outside, in the shadow of the school buildings, they drew for the honour of investigating the room of Mr. Daw, and the shortest straw fell to the lot of Jack.
"You can go up now," said Fane, suddenly. "I remember that Daw went out this evening, and he hasn't come back yet, for he'd have to pass the boot-room to do so. If you're slippy you can get up there, examine the boots and get away again in about a minute."
"I'll do it," said Jack, as they came through once more to the corridors of Salmon's House. He rubbed his chin with his forefinger. "Let me see," he asked, "isn't there an electric torch of yours in the study?"
"Of mine?" said Billy doubtfully. "We'll see." They proceeded to the study, and there Billy unearthed an old, but still serviceable, torch. Armed with this, Jack went upstairs to the upper floor, where the masters' rooms were.
"Tit for tat," he murmured, turning the handle of Daw's door and opening it quietly. He let himself inside, and closed the door noiselessly. For half a minute he stood still, to assure himself that Doctor Daw had not returned, and then, flashing his torch, made a hurried search for the master's boots. He found a few pairs, all showing signs of recent use, but none with the distinctive tag.
"Ten to one he's wearing them," murmured Jack. At that moment his heart beat furiously. Steps were coming along the corridor, and they stopped outside the door. For a second he was paralysed; then he acted swiftly. He had barely time to roll under the bed before Doctor Daw himself entered the room—and with him his strange friend Tiger!