  Without waiting for the gelatin to harden, Roger summoned the staff and his cousin to the screening room. As soon as they had set their wrist watches with the observatory time signals, a routine part of the staff’s accuracy, they joined him. He had the tender emulsion-covered celluloid threaded from the top magazine through film gate and take-up sprockets down to the lower magazine of the projector. In the small, compact theatre, with its platform for lecture and demonstration procedure, its large screen, easy chairs, loud speakers and apparatus, he showed Grover and the men what caused him to agree with Tip. “It almost has to be a snake,” Roger declared. No other than a creeping thing could drag over a step edge. Four footed creatures, he explained, did not disturb dust at the point indicated in close-up and wide-angle pictures, greatly enlarged by the projector. The chief electrical specialist, Mr. Ellison, agreed. “It ends the mystery. A snake ate the rats.” “Then there won’t be any disease epidemic,” Doctor Ryder was much relieved, “It will crawl somewhere and the germs may destroy the reptile.” To this Mr. Millman, electrical engineer; Mr. Zendt, bio-chemist; Mr. Hope, their analyst, and others, agreed. Roger saw that his cousin reserved opinion. But routine had to go forward, and the staff men separated. Zendt went to resume experiments in the search for a dye of a certain desired shade and quality: the two electrical men were busy developing means to find a better way to insulate high-tension cable for carrying electricity from generators to distributing stations in small communities; the others had equally absorbing work in progress. Grover, busy examining each picture projected and held on the screen without danger of the “cold” light igniting the protected film, gave Roger a dozen cellar views around the coal-chute to enlarge. “Make ten-by-twelve bromide enlargement prints,” he ordered. Roger, although it seemed impossible that anyone could have moved the stiff rusted bolt inside the trapdoor of the coal chute, a trap that lifted up and out onto the street, said no word of objection. He felt that Grover would find nothing in the enlargements. Expertly he adjusted paper on the camera-stand, extended the bellows to secure most perfect focus, made his exposures, developed, and fixed the large prints, and took them to his cousin’s own den. “As I expected—nothing!” he reported. “No abrasions of the bolt, or edge of the trap?” “You mean, where someone inserted a ‘jimmy’ to shove back the bolt?” Grover nodded. “Not a thing shows.” Roger asserted. His cousin did not accept his statement; but his disappointed eyes told Roger that the examination he had made during developing work had been accurate, thorough, and had led to a correct decision. They were at a standstill. Calls to the zoo, brought from its curator the declaration that no snake was absent from its cage, that no one of his keepers had tried to “train” snakes—as the laboratory head had half-laughingly suggested. As he left the screening room, Roger met Potts. “Tip,” he hailed, “Did you get anything on the ‘sound’ film in the one-snap-a-minute camera?” “The one that took pictures of them mouses?” “The one by the rats’ cage—yes.” “You know about sound, Rog’. It ain’t just a lot of single pictures.” Potts wanted to air his knowledge. “Sound is a maintained concession of peaks an’ valleys on the sound track.” “You always will use a .44 caliber word when a BB. size would hit what you aim at and not blow your idea to bits, Tip. You mean that sound is a ‘sustained succession’—I know that. And single frames, if they showed any sound impression at all, would give little pops.” “So I didn’t bother.” “But, Tip! There was a lot of wild zig-zag marking on the tape in the seismograph-like recorder; and it seemed as though the ‘continuous’ taking lever had been shifted before he—it—whatever was there, stopped the whole business by breaking off the wiring.” “We can try.” When they had developed the negative, made a print and fixed and washed it, Roger threaded the fifteen frames of continuous shots in place and projected with the speakers cut in. Then he rushed to get Grover. The staff too! He had a clue. As nearly as he could have described the brief sound made and amplified with transformer-coupled, matched metal audio tubes of the most perfect type giving the speakers power, they had picked up a sound of hot grease sputtering, hissing and clicking, as it does if sausage is fried rapidly. “Come on, Ear Detective,” chaffed Mr. Millman, “Who was frizzling sausages on the cage full of inoculated rats, so that the mike inside picked it up and took it on to the sound film?” “That’s not sausage frying,” exclaimed the biochemist, “Someone had steam up and the mike picked up the sound the radiator valve made as air was expelled and steam arrived to close it spasmodically.” “A microphone, inside of a glass cage top?” mocked Mr. Ellison. “How could a valve on a radiator across the room make all that noise?” “Let the Ear Detective explain it,” urged Mr. Hope. They all turned to Roger. He shook his head. “It does sound most like the snick-snap, and sizzle, of sausage,” he admitted, “But——” “It’s a snake, I say,” Potts defended his theory; “a snake, with hissing and his scales rattling on the glass when he was crawling up to dig his head in and grab breakfast.” “What’s your idea, Grover?” asked Mr. Hope. “Sounds as much like a snake as anything I can imagine, Sam.” “So say I,” agreed Mr. Ellison. “Are we right, interpreter?” Potts got the correct word, for once. Roger hesitated. Not that he cared if he lost his reputation as a young person able to read correctly what his sensitive ears caught; Roger was not vain or self-satisfied. He was not the sort to make a statement just to hold up his reputation. In some ways the sound might be such as a snake, with its hide striking or rubbing, as it hissed, could make; but, again, a lizard might make that sound—or a dog, scratching on a window. He stood up, excited for the moment. “Claws on glass!” His sharp cry died into silence. They all considered it. “A snake ain’t got pedicular exuberances,” objected Potts. “Pedal protuberances, eh, Tip?” chuckled Mr. Hope, “What do you say, Grover?” As Roger looked toward his cousin he saw what surprised him most of all that had so far happened. Never in his stay at home or laboratory, intimately close to the scientifically brilliant, but poised, cousin, had Roger seen him lose his calm. Now, Grover stood up, and in his eyes was the same sort of light of satisfaction and triumph that a boy would show when he had successfully smuggled in and hidden mother’s birthday present. “Roger is absolutely right!” “Claws on glass? A big dog?” asked Mr. Zendt. “Remember the cellar step clue.” “A lizard?” Mr. Ellison suggested. “Remember Tip’s statement about how he was knocked senseless.” “Oh—a man with a—a what?” Mr. Millman was not so confident of his deductive ability. He paused. “I will leave you to work it out,” Grover beckoned to Roger; “I must run out to the zoo.” He was as eager and elated as a boy with a new football. He beckoned to Roger who followed as his cousin got his hat. “I want you to go to all the newspaper offices. Take a taxi. Get back issues for the past two weeks, maybe you’d better get them for three weeks back.” “You know?——” “I have two theories. I want to make sure which is right.” “Do you really think I got the right meaning out of the hisses?” “Precisely the correct meaning.” “But it doesn’t tell me anything, cousin Grover.” “Use my formula. Dig past appearances that can be falsified, to the truth. Marshal your facts, test each one, eliminate the impossible and what you have left is the truth.” Telephoning to summon a taxi for Roger, the laboratory head was busy for a moment. Roger tried to employ the method just named. Youth, inexperience in doing such consecutive and eliminative thinking, he knew, hampered him. With a mind trained, through solving chemical, electrical and other industrial experimental difficulties, Grover’s clever mind had skipped many of the links that Roger, slowly, had to take up and examine. He was in the taxi, with bundles of back issues of the city papers, on his way back, and still his mind was a maze of unfitted details. In the office, combing the papers for notes about snakes, or any other escaped reptile—he had to keep in mind that trail on the edge of the steps alone!—he got nowhere. No news showed up about lost, stolen or escaped animals or any form of brute or reptile. Grover, he saw, had returned, and was not joyful. “One theory went to smash,” he said, “I verified your sound—claws on glass was the right deduction. But—that doesn’t bring what I want.” “What do you want?” asked Roger, eagerly. “To capture the culprit.” “Won’t the police?——” “We have no justification for calling them in. Nothing has been stolen. Nothing has been harmed.” “The rats——the menace to the public!” “Roger, you haven’t studied those films Potts took.” Roger got them at once, projected, one at a time, examining the screen images carefully. The cellar views, only proving that some object left no other trace of progress than scraped dust on step-edges, he considered and discarded. Those taken by windows, doors, intakes and outlets of the air-conditioning, and gas-exhausting roof, cellar and wall orifices gave no revealing clues. When he got to the wide-angles of the lower floor and stairway, and found no reward for his long scrutiny, Roger was baffled. Only the micrometric enlarged snaps and one time-exposure near the X-ray devices remained. He considered them ruefully. They gave no foreground evidence to help him. Roger, with defeat creeping over his feelings, was about to give up. He was fair, he told himself, when it came to interpreting sounds, but at the more important quality of being able to connect the clue with everything else, he was “stumped.” What could those enlarged views hide from him? The walls, with racks of test-tubes, some containing chemical solutions, others holding cultures of various forms of growth that Mr. Zendt had accumulated or was studying, told him—— He stared, bent closer, climbed up on a chair close to the screen! After two minutes of close scrutiny, he jumped to the floor, and raced to find Grover. “Just by chance, in taking the micro-lens pictures,” he gasped out, “Tip got in some of the test-tubes. Is that what you saw?” Grover, smiling, agreed. “What did it tell you?” “I arranged those racks yesterday. I have got a good memory.” “I knew both those facts,” Grover admitted, “and I, too, helped in revising our arrangement of the racks. Go on!” “The tubes that held the culture of the spinal disease germs—so dangerous that they had been delivered, personally, by the medical center bacteriologist, had blue labels!” “You are ‘warm’ as the hide-and-seek game puts it.” “I saw Doctor Ryder take them up, in his surgeon’s clothes to prevent infection.” “So did I.” Grover acknowledged the fact. “He actually took two tubes that must have had the right labels because he would have seen what they were marked.” “Labels can be soaked off and transposed from one tube to another, Roger.” “I think that happened. He took them, went up, and we both saw him use the hypodermic needle.” “But—” Roger could hardly restrain his thrill at having made as clever a discovery as the coming one: “Those two tubes—full!—are in back of others, right now. Not the two empty ones he incinerated to be sure the germs were all destroyed.” “They are? How did you discover it?” Roger told him: “Our chemical labels that are a green, photograph a darkish gray; and our culture labels, that are a buff, photograph lighter, but still grayer than white paper. The poisons are labeled red and come out in a picture almost black. “But blue except very dark shades, will photograph nearly white! And those two labels, hidden in a dark corner, show up in the picture where they might not be noticed in the rack.” “Can you go further and say why no culture was allowed to be given, although the inoculator evidently thought his serum was genuine?” “Whoever was going to take the rats, did not want them to be dangerous to him.” “Very nicely argued out, Roger,” his cousin complimented him. “Now, we must find a way to draw that criminal who trains animals to do his work, into the open where police can get him.” |
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