Sherlock’s opportunity to learn the results of his night’s work did not come until the middle of the morning. The Lenape program gave no freedom for detective labors until the period after squad-work had been completed. Tent Ten had been assigned to policing the lodge, and as Sherlock bent over his broom he cast many a dark glance at the busy Utway brothers, fretting until the moment came when he would be able to take his exposed film to the dark-room and discover the results of his snapshotting expedition. At last Assembly sounded, and he headed for his tent, carefully removed the film, and made his way to the small dark-room that had been built under the lodge for the convenience of camper photographers.
36

As he shut the door, turned on the red electric bulb, and began laying out hypo and the rest of the developing kit, he heard voices from the kitchen directly overhead. Ellick was superintending the preparations for lunch, and from his tone it was evident that his temper was not as genial and kindly as usual. Ellick, it would seem, had a grievance.

“Ah don’t no-how likes to think of a thief about de camp, Leggy,” he complained. “Ah gives de boys and de councilors all dey can eat. Whaffor dey want to come stealin’ around in de night to get bread and such?”

Sherlock pricked up his ears. Here was another case for a bright detective! Stealing from the kitchen! He awaited Leggy’s reply.

“Don’t know, Chef!” the assistant answered. “You-all figure, maybe dey gets hongry in de night, and a chunk o’ bread look mighty nice.”

“Don’t talk foolishment! Whaffor dey have to bust de lock on de pantry window jest ’cause dey gets a cravin’ for a snack? And what about de ax? Suppose dey wakes in de middle o’ de night and gets a cravin’ to chop down a few trees? Mah best hand-ax, stole right off de woodpile! No suh, I don’t like to think any Lenape fellow goes about bustin’ into windows and swipin’ dangerous wood-axes when folks is sleepin’.”
37

“How much grub did dey-all take, Chef?” came a question in the voice of Howard Chisel, the squat, bow-legged, ebony-faced lad who presided over dishwashing operations. “Jest bread?”

“No. More’n dat. Got off wid a couple cans o’ truck, and maybe some potatuhs. Ah declare, if Ah don’t tell de Chief about dis fust thing. Hookin’ a doughnut now and den is jest boy-tricks. Bustin’ windows and stealin’ good sharp axes is somethin’ else again!”

The listening boy made a note to ask Ellick for further details of this latest crime. At present, he was too busy to lend his services in another case. His hand shook slightly as he dipped the film in the developing baths, watched with eyes glittering behind their large lenses as the smoky negative cleared into masses of dark and light in the bottom of the tray. Most of the surface was taken up with a black patch that was in all likelihood the canvas of Tent Fifteen, but he would have to make a clear print of the scene before the details would show beyond question. He hung the fixed negative to dry and went out into the sunshine to wait impatiently until a proof could be taken.
38

Sherlock kicked his feet against a rock and thought over all the information he had gathered about the Utway affair. He hoped that the print he was making would show without question the full villainy of the twins. If it did not, it would leave him in a predicament. Mr. Colby had not seen either of the Utway twins, who had made their ways back to their bunks without capture. Yes; the picture must be a good one. Sherlock rose and went back into the dark-room.

With all the skill and care of which he was master, Sherlock Jones toiled over the developing of the first print of the raiding scene. Eagerly he bent over the developing bath as dark edges began to take shape on the bit of white paper. Slowly, slowly, the details melted into being, seeming to spring from the waters above the print. Now! The boy switched the print into the fixing tray, turned on the white light, and scrutinized his handiwork.

One glance, and he was ready to cry out with disappointment. He bit his lip. The explosion of the too-generous quantity of flashlight powder had startled him, and in his haste, unsure of his hearings in the darkness, he had twisted the camera on its tripod so that none of the action was visible. Diagonally across the picture ran the rear flap of the tent. The head and pillow of Mr. Colby showed with clearness, but the forms of the Utway twins and Alexander the frog were cut off by the expanse of the tent-fly. All that the picture revealed was a peaceful night-scene in one corner of Tent Fifteen—nothing more.
39

Had Sherlock not reminded himself that a good detective never gives way to emotion or shows in his features the state of his feelings, he might have stamped up and down the dark-room, raving at his failure. As it was, he controlled his disappointment as best he could, and patiently went over the picture a second time, to make sure that no detail had escaped his notice.

He was rewarded. In the upper corner of the print was something which at first glance he had not seen. It appeared to be an arm, the hand gripping one of the tent-ropes, the upper part near the body cut off by the edge of the negative. With growing excitement, Sherlock drew from his pocket the small magnifying lens he carried with him at all times. Taking the wet print into the outdoor sunshine, he focussed his glass on the mysterious detail. It was an arm—and the lens showed plainly a mark by which a detective could distinguish this arm from all other arms in the vicinity. Upon the fleshy part of the under forearm was tattooed the sketchy design of an American eagle with outstretched wings.
40

Here was a clue, indeed! Sherlock quivered with renewed hope. The arm could not belong to Mr. Colby. Although he could not say for sure, he had never noticed that either of the Utway twins bore such a tattoo mark, and it was unlikely that they could have kept secret such a distinctive brand. Therefore they must have had with them an unknown accomplice whom Sherlock, in the confusion of the moment, had not caught sight of at the time of the raid.

Who could it be? He thought over all the names of the campers of Tent Fifteen. He could remember no one who wore on his arm the patriotic stamp of an eagle. Well, there was one way of finding out. He could examine every arm in camp. And this could be done quite easily when the entire strength of the Lenape campers gathered on the dock for swim.

The bugle-notes of Swim Call sounded over his head as he hastily cleared away his developing paraphernalia and hung the precious print to dry, hidden in a far corner. He put away the negative in his breast pocket and raced down to his tent to change into swimming togs. Within a few minutes he was on his way to the boat-dock at the edge of the lake. He had already decided to refer to the Utway case in the future as “The Clue of the Tattooed Arm.”
41

The life-saving crew was already on duty, although only two or three younger campers had made their appearance on the plank floor of the dock. As Sherlock watchfully stepped out toward the far end, Wally Rawn, the husky leader who directed swimming and was captain of the life-saving organization made up of expert leaders and older boys, was shouting to a black-haired boy wearing the crew emblem. This boy, Steve Link by name, was rowing a round-bottomed steel rowboat some hundred yards out beyond the diving-tower. Attached to the stern painter of his craft was one of the camp canoes, which he was towing across the water with heaving oar-strokes.

“Where did you spot her, Steve?” Wally was shouting.

Steve rested on the handles of his oars. “Way down almost to the dam!” he answered. “She must have got loose last night and drifted with the current. Had the dickens of a time finding her, too!”

“Carelessness!” Wally Rawn muttered, shaking his head. “Somebody played the dub and didn’t even tie up after using it. I’d think even a tenderfoot would know that a canoe should be brought up and turned over on the dock after a trip. A good way to lose a fine canoe!”
42

He raised his arm to blow the whistle that would begin the swimming period, and Sherlock made sure that Wally Rawn, at least, had no tattooed eagle on his left arm. The dock was now crowded with campers, and the shrill call had no sooner sounded than the air was full of diving bodies and splashing spray as the boys of Lenape took to water. The life-saving boats were now at their posts, guarding the safety of the swimmers.

Sherlock remained on the dock, where he had a full view of everyone. His head jerked back and forth as he tried to follow every move of the group of swimming boys, now grown to almost the full number of the camp. He caught sight of Jerry and Jake Utway, whose flying bodies curved through the air from the highest diving-platform and almost at the same instant cleft the rippling surface of Lake Lenape. He watched them moodily as they swung hand over hand toward the farthest lifeboat. At any rate, neither of them bore a tattooed eagle on his arm! He must find the mysterious accomplice. With renewed energy he swept the sportive, glistening bodies of the gay swimmers with an intent gaze.
43

When the final “All out!” whistle blew, the dejected Sherlock made his way up the hill. He was baffled. His vigil had not revealed an incriminating tattoo-mark on the arm of any of the campers or leaders present. He must be patient and watchful, trusting to luck and his skill at shadowing the suspected twins to bring forth some fresh clue.

As he entered Tent Ten, the only one of his comrades before him was little shock-headed Pete Lister, youngest and smallest lad in the tent-group. The kid looked up as Jones came up the step.

“Hey, Sherlock, look what I’m doing!” He squirmed over in his seat on the unmade bunk, and waved an indelible pencil in the air. “See? Making pictures, I am! Bet you never thought of this, Sherlock!” He stuck out one sunburnt leg. The calf and thigh were a mass of scrawled, deep-purple designs—crooked anchors, shaky outlines of American flags, hearts, daggers, skulls, and Pete’s own name in wavering characters. “You don’t need to worry—they come off easy. See? First you draw ’em, then you wet the picture a little, and I’ll bet you couldn’t tell ’em from a real tattoo-mark! Want to try it?”

“No. No, thanks,” said Sherlock Jones bitterly.