hutchinson hatch, reporter, was standing in a corner with both hands in his coat pockets. just three inches to the left of his second waistcoat button was the point of a stiletto, and he glanced at it from time to time in frank uneasiness, then his eyes returned to the flushed, tense face of the girl who held it. she was italian. her eyes were splendidly black, and there was a gleam in them that was anything but reassuring. her scarlet lips were parted slightly, disclosing small, regular, white teeth clenched tightly together. a brilliant multicolored headdress partially confined her hair and rippled down about her shoulders. her skirt was barely to her ankles.

“i feel like the third act of an italian comic opera,” hatch thought grimly. then aloud, “what is all this?”

“you must be silent, signor!” warned the young woman in excellent english.

“i am going to be,” hatch explained; “but still i should like to —”

“you must be silent, signor!” the girl repeated. “no, don’t take your hands from your pockets!”

“but look here!”

the stiletto point was pressed in until he felt it against his flesh. he winced involuntarily, but wisely held his tongue. it was a time to stand perfectly still and wait. he had come to the tenement in the course of his professional duties, and had rapped on this door to inquire in which apartment a certain family lived. the door had been opened by the young woman — and now this! he didn’t understand it; he didn’t even make a pretense of conjecturing what it meant. he just kept on standing still.

from outside came the varied noises of a busy city. inside the gloom grew about him, and gradually the rigid, motionless figure of the girl became a shadowy silhouette. then an electric arc light outside, which happened to be on a level with a window, spluttered and flashed into brilliance almost blinding him. through the murk of the room only their motionless figures were visible.

after awhile the reporter heard vaguely a stealthy shuffle of feet as if some one was passing along the hall. then the door leading from the hall into the next room opened and closed softly. the girl prodded him with the stiletto point to remind him to be silent. it was a needless warning, because now hatch dimly foresaw some grave and imminent danger to himself in the presence of this third person, whoever it might be. unconsciously he was concentrating all his forces, mental and physical, for — for something he didn’t know what.

the shuffling feet were now in the next room. he heard them moving about as if coming toward the connecting door. then a hand was laid on the knob, the lock rattled a little, and the door was softly closed. hatch took a deep breath of relief — whoever this third person might be, he evidently had no business in the room with them just at that moment.

with straining ears and tense nerves the reporter listened, and after awhile came a muffled chatter as of some one talking rapidly and incoherently. then he heard a man’s voice, pleasant neither in tone nor in the expletives used, and several times he heard the chatter — quick, excited, incoherent. at last the man broke out into a string of profanity, objurgations. the chatter rose angrily, and burst finally into a strangling, guttural scream of anguish.

with a chilly creepiness along his spine and nerves strained to the breaking point, hatch started forward involuntarily. the stiletto point at his breast stopped him. he glared at the rigid figure of the girl and choked back, with an effort, an outburst of emotion. his utter helplessness overwhelmed him.

“some one is being killed in there!” he protested desperately between gritting teeth.

“sh-h!” warned the girl.

from the next room came the shuffling of feet again, then a soft thump thrice repeated, and a faint gurgling cry. hatch shivered a little; the girl was rigid as marble.

“i guess that fixed you!” hatch heard a man say.

there was silence for a minute or so. the feet moved stealthily again, and the door leading from the other room into the hall opened and closed. the footsteps moved rapidly along, then apparently precaution was forgotten, for they clattered down the steps and were gone.

suddenly the girl straightened up. “you will remain here, signor,” she said, “until i am out of the house? you will raise no alarm for at least five minutes? believe me, if you do, it will be worse for you; for sometime, somewhere, you will have occasion to regret it! you promise?”

hatch would not make himself believe that he had the slightest choice in the matter. “i promise, of course,” he said.

she bowed a little, half mockingly, flung open the door, and ran out. hatch heard the swishing of her skirts as she sped down the stairs, then he brought himself together with a huge sigh and a nervous jerking of his limbs.

he strode across the room twice to regain possession of jumping nerves, then paused and lighted a cigarette. what was in the next room? he didn’t know. he wanted to know, and yet there was an intangible fear which clung to him and held him back when he started for the door. at last he mastered this absurd weakness, and flung the door open wide, and walked in. at first he saw nothing, and he had expected to see every evidence of a brutal crime. then in a far corner he noticed what seemed to be a bundle of rags which had been thrown there carelessly. he strode over boldly and poked it with his foot, stooping to examine it.

what he saw brought an exclamation from him; but it was rather of astonishment than of horror. the thing he had found was the body of a monkey. the rags were the tawdry clothing in which organ grinders attire their apish companions. there was a little cap, a coat, and trousers.

“well! what in the deuce —” exclaimed the reporter. he dropped on his knees beside the tiny body. there were three stab wounds in it — one in the throat and two in the breast. the body was still warm.

“but why,” protested hatch, “should anyone, man or woman, murder a monkey?”

professor augustus s. f. x. van dusen — the thinking machine — didn’t hazard a conjecture. “are you sure it was a monkey that was murdered?” he asked instead. “i mean are you sure that only a monkey was murdered?”

“i am sure,” he responded emphatically, “that the monkey was killed while i listened, and certainly there was nothing else that i could find or that i heard to indicate anything beyond that.”

“did you search the place?” queried the scientist.

“yes.”

“find anything?”

“no, nothing.”

“did you happen to notice, mr. hatch, if the monkey’s clothing had pockets?”

“there were no pockets. i looked for them.”

the thinking machine lay back in his chair, steadily squinting upward for several minutes, without speaking. then: “i can comprehend readily why the monkey should have been killed as it was. any one of half a dozen hypotheses would explain that. but if the monkey didn’t have a pocket somewhere in its clothing, then i don’t see so readily why — oh, of course — must have been bigger than i thought,” he mused.

“what?” inquired hatch.

“are you sure, mr. hatch, that there had been nothing sewn to the clothing of the monkey?” asked the thinking machine, without heeding the question —“that nothing had been ripped loose from the clothing?”

“i can’t say as to that,” the reporter replied.

“where is the monkey now?”

“still there in the room, i suppose. i came straight from there to you here. of course, my being held up that way wasn’t of any actual consequence — it was merely incidental, i thought, to the other.”

the thinking machine nodded. “yes,” he agreed. “i presume that was merely because you happened to arrive at an inopportune moment, and that method was employed to keep you out of the way until whatever was to be done was done.”

the thinking machine and the reporter went out together. it was a few minutes past nine o’clock when they reached the tenement. it was dirty and illy lighted, and boldly faced a street which was a center of the italian colony. hatch led the way in and up the stairs to the room where he had left the monkey. the little body still lay huddled up, inert, as he had left it.

by the light of an electric bulb the thinking machine examined it closely. twice hatch saw him shake his head. when the thinking machine arose from the floor his face was inscrutable. he led hatch around that room and the next and through a third which connected, and then they went out.

“it is an extraordinary case, mr. hatch,” he explained as they went on. “there are now three explanations of the affair, either one of which would fit in with every fact that we know. but instead of helping us, these three possibilities make it necessary for us to know more. two of them must be removed — the remainder will be correct as surely as two and two make four, not sometimes but all the time.”

hatch waited patiently.

“the real problem here,” the scientist continued after a moment, “is the identity of the person who owned the monkey. when we get that, we get a starting point.”

“that would not seem difficult,” hatch suggested. “it is extremely improbable that anyone knows of the affair except the persons who were responsible for it, perhaps the owner of the monkey and ourselves. an advertisement in the newspapers would bring the owner quickly enough.”

“there is always the possibility, mr. hatch, that the owner is the man who killed the monkey,” replied the scientist. “in that event the advertisement would do no good; and there is a question if it would be advisable to let those persons who are responsible for the animal’s death know that the matter is being investigated. this is presuming, of course, that some one besides the owner killed it. it will be just as well to let the young woman who held you prisoner believe that the affair is at an end. any other course just now might indirectly endanger the life of some one who has not yet appeared in the case.

“i am going home now, mr. hatch,” concluded the scientist, “and it is possible that within two or three hours i may devise a plan by which we can find the monkey’s owner. if so, i shall communicate with you.”

“you can reach me at police headquarters until about midnight,” replied the reporter. “i am going up there on another affair.”

it was about a quarter past eleven o’clock that night when hatch scurried away to a telephone and eagerly cried to the thinking machine, “i know the man who owned the monkey!”

ten minutes later he was in the scientist’s little reception room. “the man who owned the monkey,” he said, “is named giacomo bardetto. he is an organ grinder. he was found unconscious in an area way at the other end of the city tonight at ten o’clock. he had been struck down from behind, his organ smashed, his pockets rifled, and no one knows how long he had been unconscious when found. he is now in a hospital, still unconscious. the police know nothing whatever about the monkey incident; but i surmise that the dead monkey was bardetto’s. you might have noticed that a short chain was attached to the monkey’s clothing? the other end of that chain is fastened to the hand organ.”

“how was bardetto identified?” asked the thinking machine.

“by his organ grinder’s license, which was fastened to the inside of a flap on the instrument.”

“his home?”

“here is the address,” and the reporter produced a card on which he had jotted down the street and number.

the thinking machine studied the card for a moment, then glanced at his watch. it was five minutes of midnight.

“detective mallory sent a man there to notify his family of bardetto’s condition,” hatch went on to explain. “but it seems that he has no family or relatives. mallory, of course, has nothing to lead him to think that the case is anything more than ordinary assault and robbery.”

“let’s go see what the case really is, mr. hatch,” said the scientist. “i know in a general way what it is, of course; but it possesses many singular features.”

half an hour later they stood in the room where bardetto lived. this too was in a tenement and poorly furnished. it seemed to be a combination of bed room, living room, dining room, and kitchen. the thinking machine began a minute search of the room. bureau drawers were pulled out, the bed denuded, articles of furniture moved, and even the oil stove turned upside down. hatch stood looking on without the slightest idea of the object of the search.

“what are you looking for?” he asked at last.

“i don’t know,” the thinking machine confessed frankly. “the ultimate purpose is to find out why the monkey was killed. i have an idea that there is something here that will answer the question.”

and the search continued. every conceivable point seemed to have been gone over; and hatch was marveling at the thoroughness of it, when the thinking machine dropped on his knees on the floor and wriggled along, minutely inspecting the baseboard at every joint. one of these sounded unlike the others when he rapped it, and he began work at it. finally the board responded to the prying of a knife and fell out. the thinking machine took one look.

“dear me! dear me!” he exclaimed in a tone which nearly indicated astonishment.

he plunged both hands into the narrow aperture and tumbled out on the floor package after package of money — crackling, rustling bills — unfolded and with the sheen of newness still on them. there was money and money! hatch stared with bulging eyes.

“now i know why the monkey was killed,” remarked the thinking machine conclusively. “this is what i was looking for, but i didn’t know it.”

“great scott! whose is it? how much is there? where did it come from?”

hatch flung the questions at the diminutive scientist still crouching on the floor. the thinking machine glanced at him in petulant reproof at an excitement which the reporter’s voice betrayed.

“whose is it?” he repeated. “bardetto’s. how much is there? i should say from fifty to seventy-five thousand dollars. it’s all in two and five dollar bills. where did it come from? i should say that it came from the —”

the door behind them squeaked a little as it swung on its hinges. hatch turned quickly. it was the girl. for an instant they stood motionless, staring at each other in mutual astonishment. the thinking machine didn’t even glance around.

“put that woman under arrest, mr. hatch,” he commanded irritably, “and close the door! she has no revolver, but look out for a knife.”

hatch pushed the door to with his foot. “now, signorina,” he remarked grimly, “i shall have to ask you to remain silent.”

the girl was evidently not one of the screaming kind, but her right hand disappeared into the folds of her dress as she faced him boldly. it was a sinister movement. hatch smiled a little, and his own right hand went back to his hip. perhaps he smiled because he had never been guilty of carrying a revolver in all his life.

“don’t do that, signorina!” he advised pleasantly. “don’t make any mistake with that knife! i have never drawn a revolver on a woman, and i don’t want to now; but believe me, you must take out the knife and drop it. you must, i say!” and his right hand moved forward the fraction of a foot threateningly.

staring straight into his eyes without a tremor in her own, the girl produced the stiletto, and it clattered on the floor. hatch kicked it beyond her reach. the thinking machine finally arose from his place on the floor.

“mr. hatch,” he commanded sharply, “take the young woman over in the far corner there and let her sit down. just so surely as she makes any noise, however slight, it will cost one of us, perhaps even both of us, our lives. remember that and act accordingly. don’t hesitate an instant because she happens to be a woman. i shall be able alone to take care of whoever else may happen to enter.”

the tone was one which was utterly strange to the reporter, coming as it did from this crabbed, irritable little scientist whom he had known so long. it was chilling by reason of its very gravity, and for the first time in his life hatch felt that his companion considered a situation imminently dangerous. all of which convinced him that if he had ever obeyed orders now was the time. the girl’s face was white, but there was a slight, mocking smile wavering about her lips.

the thinking machine turned the gas half down, then went over and sat near the door. silently they waited, five, ten, fifteen minutes; then they heard a quick, muffled tread moving along the hall toward the door.

“if she moves or makes the slightest sound, shoot!” directed the thinking machine in a low voice.

he arose and faced the door. some one fumbled at the lock, and the door swung inward. the figure of a man appeared.

“hands up!” commanded the thinking machine abruptly, and he thrust a glittering something beneath the intruder’s nose. the man’s hand went up. the thinking machine leaned forward suddenly and deftly abstracted a revolver from the stranger’s right hand pocket. he gave a sight of infinite relief as he straightened up, holding the captured revolver in hand.

“it’s all right, mr. hatch,” he said to the reporter, who had scarce dared remove his eyes from his prisoner. then to the man and woman, “it may interest you to know that neither of us had a weapon of either sort until i got this revolver. i stopped you,” he told the man, “with a clinical thermometer, and mr. hatch captured you,” he told the woman, “at the point, we may say, of his pipe case.”

they were all at police headquarters — the thinking machine, hatch, and the two prisoners. piled up on detective mallory’s desk were the packages of bills which the scientist had discovered. they were counterfeit, all of two and five dollar denominations, and excellent in texture, engraving, and printing. but the numbers were at fault; all the twos were the same, and all the fives were the same.

for the enlightenment of detective mallory, the thinking machine and hatch repeated in detail those incidents leading up to the capture of the man and the woman.

“there is really little to explain,” said the scientist at the end; “although the problem, while it lasted, was one of the most complex and intricate i have ever met. we may dismiss mr. hatch’s first adventure as of no consequence. it just happened that he went to the house on a different matter, and fortunately was dragged into this affair. now, i have no doubt that the prisoners here will give us the location of the counterfeiter’s plant?”

he glanced at the man and woman. they looked at each other, but remained silent.

“i have never met a counterfeiter yet who would give up the hiding place of his plates,” remarked detective mallory.

“but these are not counterfeiters, mr. mallory,” said the thinking machine; “they are merely thieves. bardetto, the man who was found unconscious, who owned the monkey, is one of the counterfeiters. let me explain briefly how every fact considered clears up the problem. first, the inevitable logic of the affair shows us that these two prisoners learned in some manner unknown that bardetto was either a principal or an agent for some big counterfeiting scheme; for we can’t believe that they thought this was real money. but instead of reporting the matter to the police they resolved to benefit by it themselves. how? by stealing the bills from bardetto, this to be followed, perhaps, by immediate flight to italy. they are both italians, and you may know that a clever american counterfeit abroad is almost as good as the genuine; and for that matter these bills would pass in circulation readily here.

“granting, then, that they did know of bardetto’s part in the scheme, we can readily imagine that they learned that bardetto had a quantity of the money in his possession; so the robbery was planned. the man here did the work, and was to meet the woman in the vacant rooms of the tenement where mr. hatch saw her.

“well, bardetto was attacked and his pockets rifled. evidently our prisoner did not find what he sought, and yet he knew that the money had passed into bardetto’s possession, and perhaps too that he had had no opportunity of getting rid of it. was it in the organ? he smashed it to see. it wasn’t. then, the monkey: was the money concealed about the animal’s clothing? that was the next question in the robber’s mind.

“half a dozen reasons, such as some one approaching, would have prevented this man making a search there; so he broke the monkey’s chain and took the little brute along with him. in the vacant apartments the man did not meet the woman — we know why — perhaps presumed that she did not come, and so went on with his search. it is extremely probable that the monkey struggled and fought in the hands of a stranger, so the man stabbed it. he had no use for it, anyway. now, as a matter of fact,” and the scientist turned to the man whom he had personally taken prisoner, “you took a pouch or pocket from beneath the monkey’s clothing, didn’t you?”

the prisoner stared at him an instant, then nodded.

“so he got that counterfeit money which he knew had been in bardetto’s possession,” continued the thinking machine. “it was not a great deal — not so much as he had anticipated, we’ll say — then he and the woman planned to search bardetto’s room for more, knowing he was in the hospital. perhaps the woman went ahead to reconnoiter. i didn’t see her enter, but knew it was a woman because her skirts swished, and told mr. hatch to lose no time in arresting her.

“the minute i found the money i knew the solution of the affair — the solution that must be correct. up to that time i had imagined a dozen other things — jewels, letters, papers of some sort. that is why i told mr. hatch i didn’t know what i was searching for.” there was a pause. “i think, perhaps, that explanation covers it all.”

“i still don’t see why hatch should have been held up,” remarked detective mallory.

“it might have been merely excess of caution,” was the reply, “or the woman might have admitted him first under a misapprehension as to his identity, and was afraid to let him go. it was almost dark in the hall.”

“but why should bardetto entrust the money to the monkey?” hatch inquired curiously. “it seems to me that it would have been safer for him to carry it himself.”

“on the contrary,” was the reply. “a man in his position is always expecting arrest. if the money had been found on him, it would have convicted him; if it had been found in his organ, and that should have fallen into other hands and been identified, it would have convicted him. but if the money was on the monkey, which couldn’t talk, and he felt himself in danger, it would have been easy to free it, and perhaps it could easily have succeeded in making its escape.”

the two prisoners willingly informed detective mallory of the whereabouts of the counterfeiter’s plant — were apparently even anxious to inform him — and he in person led the raid on it. plates for the bills were seized, and five expert workers placed under arrest.

from the time hutchinson hatch was held up in the vacant room until seven prisoners were in their cells at police headquarters less than twelve hours had elapsed.