martha opened the door. her distinguished master, professor augustus s. f. x. van dusen — the thinking machine — lay senseless on the floor. his upturned face, always drawn and pale, was deathly white now, the thin straight lips were colorless, the eyelids drooping, and the profuse yellow hair was tumbled back from the enormous brow in disorder. his arms were outstretched on either side helplessly, and the slender white hands were still and inert. the fading light from the windows over the laboratory table beat down upon the pitifully small figure, and so for the moment martha stood with distended eyes gazing in terror and apprehension. she was not of the screaming kind, but a great lump rose in her old throat. then, with fear tearing at her heart, she swooped the slender, childlike figure up in her strong arms and laid it on a couch.

“glory be!” she exclaimed, and there was devotion in the tone — devotion to this eminent man of science whom she had served so long. “what could have happened to the poor, poor man?”

for another moment she stood looking upon the pallid face, then the necessity of action impressed itself upon her. the heart was still beating — she convinced herself of that — and he was breathing. perhaps he had only fainted. she grasped at the idea hopefully, and turned, seeking water. there was a faucet over a sink at the end of the long table, and innumerable graduated glasses; but even in her excited condition martha knew better than to use one of them. all sorts of chemicals had been in them — poisons too. with another quick glance at the little scientist she rushed out of the room, as she had entered, bent on getting water.

when she appeared again at the open door with pitcher and drinking glass she paused a second time in amazement. the distinguished scientist was sitting cross legged on the couch, thoughtfully caressing the back of his head.

“martha, did anyone call?” he inquired.

“lor’, sir! what did happen to you?” she burst out amazedly.

“oh, a little accident,” he explained irritably. “did anyone call?”

“no, sir. how do you feel now, sir?”

“don’t disturb yourself about me, my good woman; i’m all right,” the thinking machine assured her, and put his feet to the floor. “you are sure no one was here?”

“yes, sir. lor’! you was that white when i picked you up from the floor there —”

“was i lying on my back or my face?”

“flat of your back, sir, all sprawled out. i thought you was dead, sir.”

again the thinking machine thoughtfully caressed the back of his head, and martha rattled on verbosely, indicating just where and how he had been lying when she opened the door.

“are you sure that you didn’t hear any sound?” again queried the scientist.

“nothing, sir.”

“any sudden jar?”

“nothing, sir, nothing. i was just laying the tea things, sir, and opened the door to tell you it was ready.”

she poured a glass of water from the pitcher, and the thinking machine moistened his lips, to which the color was slowly returning.

“martha,” he directed, “go see if the front door is closed, please.”

martha went out. “yes, sir,” she reported on her return.

“locked?”

“yes, sir.”

the thinking machine arose and straightened up, almost himself again. then he went over to the laboratory table and peered squintingly into a mirror which hung there, after which he wandered all over his apartments, examining windows, trying doors, and stopping occasionally to stare curiously about at objects which had been familiar for years. he turned; martha was just behind him, looking on wonderingly.

“lost something, sir?” she asked solicitously.

“you are sure you didn’t hear any sound of any sort?” he asked in turn.

“not a thing, sir.”

then the thinking machine went to the telephone. in a minute or so he was in conversation with hutchinson hatch, newspaper reporter.

“heard of any jail delivery at chisholm prison?” he inquired.

“no,” replied the reporter. “why?”

“there has been an escape,” said the scientist positively.

“who was it?” demanded the reporter eagerly. “how did it happen?”

“the prisoner’s name is philip gilfoil. i don’t know how he got out, but he is out.”

“philip gilfoil?” hatch repeated. “he’s the forger who —”

“yes, the forger,” said the thinking machine abruptly. “he’s out. you might go over and investigate, then come by and see me.”

hatch spoke to his city editor and rushed out. half an hour later he was at chisholm prison, a vast spreading structure of granite in the suburbs, and in conversation with the warden, an old acquaintance.

“who was it that escaped?” hatch began briskly.

“escaped?” repeated the warden with a momentary start, and then he laughed. “nobody.”

“you have been keeping philip gilfoil here, haven’t you?”

“i am keeping philip gilfoil here,” was the grim response. “he is no. 97, and is now in cell 9.”

“how long since you have seen him?” the reporter insisted.

“ten minutes,” was the ready response.

the reporter was staring at him steadily; but the warden’s eyes met his frankly. there have been instances where denials of this sort have been made offhand with the idea of preventing the public from knowing the truth as long as possible. hatch knew of several.

“may i see gilfoil?” he inquired coldly.

“sure,” replied the warden cheerfully. “come on and i’ll show you.”

he escorted the newspaper man along the corridor to cell 9. “ninety-seven, are you there?” he called.

“where’d you expect i’d be?” grumbled some one inside.

“come to the door for a minute.”

there was a movement inside the cell, and the figure of a man approached the door out of the gloom. it had been several months since hatch had seen philip gilfoil; but there was not the slightest question in his mind about the identity of this man. it was gilfoil — the same sharp, hooked nose, the same thin lipped mouth, everything the same save now that the prison pallor was upon him. there was frank surprise in the reporter’s face.

“do you know me, gilfoil?” he inquired.

“i’ll never forget you,” replied the prisoner. there was anything but a kindly expression in the voice. “you’re the fellow who helped to send me here — you and the old professor chap.”

hatch led the way back to the warden’s office. “look here, warden!” he remarked pointedly, accusingly. “i want to know the real facts. has that man been out of his cell since he has been here?”

“no, except for exercise,” was the reply. “all the prisoners are allowed a certain time each day for that.”

“i mean has he never been out of the prison?”

“not on your life!” declared the warden. “he’s in for eight years, and he doesn’t get out till that’s up.”

“i have reason to believe — the best reason in the world to believe — that he has been out,” insisted the reporter.

“you are talking through your hat, hatch,” said the warden, and he laughed with the utmost good nature. “what’s the matter, anyway?”

hatch didn’t choose to tell him. he went instead to a telephone and called up the thinking machine.

“you are mistaken about gilfoil having escaped,” he told the scientist. “he is still in chisholm prison.”

“did you see him?” came the irritable demand.

“saw him and talked to him,” replied the reporter. “he was in cell 9 not five minutes ago.”

there was a long silence. hatch could imagine what it meant — the thinking machine was turning this over and over in his mind.

“you are mistaken, mr. hatch,” came the surprising statement at last in the same irritable, querulous voice. “gilfoil is not in his cell. i know he is not. there is no need to argue about it. good by.”

it so happened that professor augustus s. f. x. van dusen was well acquainted with the warden of chisholm prison. thus it was that when he called at the prison half an hour or so after hatch had gone he was received with more courtesy and attention than would have been the case if he had been a casual visitor. the warden shook hands with him and there was a pleasant reminiscent grin on his face.

“i want to find out something about this man gilfoil,” the scientist began abruptly.

“you too?” remarked the warden. “hutchinson hatch was here a little while ago inquiring about him.”

“yes, i sent him,” said the scientist. “he tells me that gilfoil is still here?”

“he is still here,” said the warden emphatically. “he’s been here for nearly a year, and will remain here for another seven years. hatch seemed to have an impression that he had escaped. do you happen to know where he got that idea?”

the thinking machine squinted into his face for an instant inscrutably, then glanced up at the clock. it was eighteen minutes past eight o’clock.

“are you sure that gilfoil is in his cell?” he demanded curtly.

“i know he is — in cell 9.” the warden tilted his cigar to an angle which was only a little less than aggressive, and glared at his visitor curiously. this constant questioning as to convict 97, and the implied doubt behind it, was anything but soothing. the thinking machine dropped back into a chair, and the watery blue eyes were turned upward. the warden knew the attitude.

“how long have you had gilfoil?” queried the thinking machine after a moment.

“a little more than ten months.”

“well behaved prisoner?”

“well, yes, now he is. when he first came he was rather an unpleasant customer, and was given to profanity, but lately he has realized the uselessness of it all, and now, i may say, he is a model of decency. that’s the usual course with prisoners; they are bad at first, and then in nine cases out of ten they settle down and behave themselves.”

“naturally,” mused the scientist. “just when did you first notice this change for the better in his conduct?”

“oh, a month or six weeks ago,” was the reply.

“was it a gradual change or a sudden change?”

“i couldn’t say, really,” responded the wondering warden. “i suppose it might be called a sudden change. i noticed one day that he didn’t swear at me as i passed his cell, and that was unusual.”

the thinking machine straightened up in his chair suddenly and squinted belligerently at the official for an instant. then he sank back again, and his eyes wandered upward. “do you happen to remember that first date he didn’t swear at you?”

the warden laughed. “it didn’t make any particular impression on my mind. it was a month or six weeks ago.”

“has he sworn at you since?” the scientist went on.

“no, i don’t think anyone has heard him swear since. he’s been remarkably well behaved.”

“any callers?”

“well, not for a long time. a physician came here to see him twice. there was something the matter with his throat, i think.”

“how did it happen that the prison physician didn’t attend him?” demanded the thinking machine curiously.

“he asked that an outside physician be called,” was the response. “he had twelve or fifteen dollars here in the office, and i paid the physician out of that.”

some new line of thought had evidently been awakened in the scientist’s mind; for there came a subtle change in the drawn face, and for a long time he was silent.

“do you happen to remember,” he asked slowly at last, “if the physician was called in before or after he stopped swearing?”

“after, i think,” the warden replied wearily. “what the deuce is all this about, anyway?” he demanded flatly after a moment.

“throat trouble, you said. how did it affect him?”

“made him a little hoarse, that’s all. the doctor told me it wasn’t anything particularly — probably the dampness in the cell or something.”

“and did you know the doctor who was called — know him personally?” demanded the thinking machine, and there was a strange, new gleam in the narrow eyes.

“yes, quite well. i’ve known him for years. i let him in and let him out.”

the crabbed little scientist seemed almost disappointed. he dropped back again into the depths of the chair.

“do you want to see gilfoil?” asked the warden.

“not yet,” was the reply; “but i should like you to walk down the corridor very, very softly and flash your light in cell 9 and see if convict 97 is there?”

the warden came to his feet suddenly. there was something in the tone which startled him; but the momentary shock was followed instantly by a little nervous laugh. no man knew better than he that convict 97 was still there, yet to please this whimsical visitor he lighted his dark lantern and went out. he was gone only a couple of minutes, and when he returned there was a queer expression on his face — almost an awed expression.

“well?” queried the scientist. “was he asleep.”

“no,” replied the warden, “he wasn’t. he was down on his knees beside his cot, praying.”

the thinking machine arose and paced back and forth across the office two or three times. at last he turned to the warden. “really, i hate to put you to so much trouble,” he said; “but believe me it is in the interests of justice. i should like personally to visit cell 9 say in an hour from now after convict 97 is asleep. meanwhile, don’t let me disturb you. go on about your affairs; i’ll wait.”

and then and there the thinking machine gave the warden a lesson in perfect repose. he glanced at the clock — the hands indicated eight-forty — then sat down again, and for one hour he sat there without the slightest movement to indicate even a casual interest in anybody or anything. the warden, busy with some accounts, glanced around curiously at the diminutive figure half a dozen times; once or twice he imagined his visitor had fallen asleep, but the blue eyes behind the thick spectacles, narrow as they were, belied this idea. it was precisely twenty-one minutes of ten o’clock when the thinking machine arose.

“now, please,” he requested.

without a word of protest the warden relighted the dark lantern, opened the doors leading into the corridor of the prison, and they went on to cell 9. they paused at the door. there was utter silence in the huge prison, broken only by the regular, rhythmic breathing of convict 97. at a motion from the thinking machine the warden softly unlocked the cell door, and they entered.

“silence, please,” whispered the scientist.

he took the lantern from the warden’s unresisting hand, and going softly to the cot turned the light full into the face of the sleeping man. for a second or so he gazed steadily at the features upturned thus to him, then the brilliant light seemed to disturb the sleeper, for his eyelids twitched, and finally opened with a start.

“do you know me, gilfoil?” demanded the thinking machine suddenly, and he leaned forward so that the cutting rays of light should illumine has own features.

“yes,” the prisoner replied shortly.

“what’s my name?” insisted the scientist.

“van dusen,” was the prompt reply. “i know you, all right.” convict 97 raised himself on an elbow and met the eyes of the other two men without a quiver.

“what size shoe do you wear?” demanded the scientist.

“none of your business!” growled the convict.

the thinking machine turned the lantern to the floor and found the shoes the prisoner had laid aside on retiring. he picked them up and examined them carefully, after which he replaced them, nodded to the warden, and they went out. the prisoner lay for a long time, resting on his elbow, seeking to pierce the gloom of the cell and corridor beyond with wide awake eyes, then, sighing, lay down again.

“let me see gilfoil’s pedigree, and i shall not annoy you further,” the thinking machine requested, once they were in the warden’s office again. the record book was forthcoming. the scientist copied, accurately and at length, everything written therein concerning philip gilfoil. “and last,” he requested, “the name, please, of the physician who called to see convict 97?”

“dr. heindell,” replied the warden — “dr. delmore l. heindell.”

the thinking machine replaced his notebook in his pocket, planted his hat more firmly on the great shock of yellow hair, and slowly began to draw on his gloves.

“what is all this thing about gilfoil, anyhow?” demanded the warden desperately. “be good enough to inform me what the deuce you and hatch have been driving at?”

“you are, i believe, an able, careful, conscientious man,” said the thinking machine, “and i don’t know that under the circumstances you can be blamed for what has happened; but the man you have in cell 9 is not philip gilfoil. i don’t know who your convict 97 is; but philip gilfoil hasn’t been in chisholm prison for weeks. good night.”

and the crabbed little scientist went on his way.

for the third time hutchinson hatch rapped upon the little door. the echo reverberated through the house; but there came no answering sound. the modest cottage in a quiet street of a fashionable suburb seemed wholly deserted, yet as he stepped back to the edge of the veranda he could see a faint light trickling through closely drawn shutters on the second floor.

surely there must be some one there, the reporter reasoned, or that light would not be burning. and if some one was there, why wouldn’t they answer? as he looked the trickling light remained still, and then he went to the door and tried it. it was unlocked. he merely ascertained that the door yielded readily under his hand, then he rapped for the fourth time. no answer yet.

he was just turning away from the door, when suddenly it opened before him, a single arm shot out from the gloom of the hall, and before he could retreat had closed on the collar of his coat.

he was hauled into the house despite an instinctive resistance, then the door banged behind him. he could see nothing; the darkness was intense. but still that powerful hand gripped his collar.

“i’ll fix your clock, young fellow, right now!” said a man’s voice.

then, even as he struggled, he was conscious of a heavy blow on the point of the chin, strange lights dancing fantastically before his eyes; he felt himself sinking, sinking, and then he knew no more.

when he recovered consciousness he lay stretched full length upon a couch on a strange room. his head seemed bursting, and the rosy light of dawn through the window caused a tense pain in his eyes. for half a minute he lay still, until he had remembered those singular events which had preceded this, and then he started up. he was leaning on one elbow surveying the room, when he became conscious of the rustling of skirts. he turned; a woman was advancing toward him — a woman of apparently thirty years, in whose sweet face lay some heavy, desperate grief.

involuntarily hatch struggled to his feet — perhaps it was a spirit of defense, perhaps a natural gallantry. she paused and stood looking at him.

“what happened?” he demanded flatly. “what am i doing here?”

the woman’s eyes grew suddenly moist, and her lips trembled. “i’m glad it was no worse,” she said hopelessly.

“who are you?” hatch asked curiously.

“please don’t ask,” she pleaded. “please don’t! if you are able to go, please go now while you may.”

the reporter wasn’t at all certain that he wanted to go. he was himself again now, confident, alert, with new strength rushing through his veins, and a naturally inquisitive mind fully aroused. if it was only a poke in the jaw he got, it didn’t matter much. he had had those before, and besides here was something which demanded an explanation.

“who was the man who struck me last night?” he asked.

“please go!” the woman pleaded. “believe me, you must. i can’t explain anything — it’s all horrible and unreal and hideous!” tears were streaming down the wan cheeks now, and the hands closed and unclosed spasmodically.

hatch sat down. “i am not going yet,” he said. “tell me about it.”

“there is nothing i can tell — nothing!” the woman sobbed.

she buried her face in her hands and wept softly. then hatch saw a great bruised spot across her cheek and neck — it might have been the mark of a lash. whatever particular kind of trouble he was in, he told himself, he was not alone, for she too was a victim.

“you must tell me about it,” he insisted.

“i can’t, i can’t!” she wailed.

and then a cringing, awful fear came into her tear stained face, as she lifted her head to listen. there was the sound of footsteps outside the door.

“he’ll kill you, he’ll kill you!” whispered the woman.

hatch set his lips grimly, motioned her to silence, and stepped toward the door. a heavy chair stood there. he weighed it judicially in his hands, and glanced toward the woman reassuringly. she had dropped down on the couch and had buried her face in a pillow; her slender form was shaking with sobs. hatch raised the chair above his head and closed his hands on it fiercely.

there was a slight rattle as some one turned the knob of the door. then it opened and a man entered. hatch stared at the profile with amazed eyes.

“by george!” he exclaimed.

then he brought the chair down with all the strength of two well muscled arms. the man sank to the floor without a sound; the woman straightened up, screamed once, and fell forward in a dead faint.

it was about ten o’clock that morning when the thinking machine and hutchinson hatch, together with a powerful cabman, dragged a man into the warden’s office at chisholm prison.

“here’s your man, philip gilfoil,” said the thinking machine tersely.

“gilfoil!” the warden almost shouted. “did he escape?”

and a moment later two guards came into the warden’s office with convict 97 between them. there were two philip gilfoils, if one might trust the evidence of a sense of sight; the first with dissipated, brutally lined face, and the other with the prison pallor upon him and with deep grief written indelibly in his eyes.

“they are brothers, gentlemen — twin brothers,” explained the thinking machine. he turned to the man in prison garb, the man from cell 9. “this is the rev. dr. phineas gilfoil, pastor of a fashionable little church in a suburb, and,” he turned upon the man whom they had brought there in the cab, “this is philip gilfoil, forger — this is convict 97.”

the warden and the prison guards stood stupefied, gazing from one to the other of the two men. the facial lines were identical; physically they had been cast in the same mold.

“the only real difference between them, except a radical mental difference, is the size of their feet,” the thinking machine went on. “philip gilfoil, the forger, the real convict 97, who has been out of this prison for five weeks and four days, wears a number eight and a half shoe, according to your own records mr. warden; the rev. phineas gilfoil, who has been in his brothers place, cell 9, for five weeks and four days, wears a number seven shoe. see here!”

he stooped suddenly, lifted one of dr. gilfoil’s feet and slipped one shoe off without even untying it. it showed no impression of the foot at all in the upper part, it was so large. dr. gilfoil dropped back weakly into a chair without a word and buried his face in his hands; philip gilfoil, the forger, his head still awhirl with the fumes of liquor, took one step toward his brother, then sat down and glared from one to the other defiantly.

“but how — what — when did they change places?” demanded the warden stammeringly. the whole thing was a nightmare to him.

“precisely five weeks and four days ago,” replied the thinking machine. “your records show that. on your own books, in your own handwriting, is a complete solution of the problem, although you didn’t know it,” he added magnanimously. “everything is there. let me see the book a moment.”

the squint eyes ran rapidly down a page, and stopped at a written entry opposite the pedigree record.

“‘sept. 3. — miss p. gilfoil, sister, permitted half-hour’s conversation with 97 in afternoon. brought permission from chairman of prison commission.’

“that’s the record of the escape,” continued the thinking machine. “philip gilfoil has no sister, therefore the person who called was the rev. dr. phineas gilfoil, an only brother, and he wore woman’s clothing. he went to that cell willingly and for the specific purpose of changing places with his brother — the motive doesn’t appear — and was to remain in the cell for a time agreed upon. the necessary changes of clothing were made, instructions which were to enable the minister to impersonate his brother were given — and they were elaborate — then philip gilfoil, convict 97, walked out as a woman. i dare say he invited a close scrutiny; it was perfectly safe because of his remarkable resemblance to the man he had left behind.”

amazement in the warden’s eyes was giving way to anger at the trick of which he had been the victim. he turned to the guards who had stood by silently.

“take this man back!” he directed, and indicated philip gilfoil. “put him where he belongs!” then he turned toward the white faced minister. “i shall deliver you over to the police.”

philip gilfoil was led away; then the warden reached for the telephone receiver.

“now, just a moment, please,” requested the thinking machine, and he sat down. “you have your prisoner now, safely enough, and here you are about to turn over to the police a man whose every act of life has been a good one. remember that for a moment, please.”

“but why should he change places with my prisoner?” blazed the warden. “that makes him liable too. the statutes are specific on —”

“the rev. dr. gilfoil has done one of the most amazing, not to say heroic, things that i ever heard of,” interrupted the scientist. “now, wait a minute. he, a man of position, of reputation, of unquestioned morals, a good man, deliberately incarcerates himself for the sake of a criminal brother who, in this man’s eyes, must be free for a short time at any rate. the reason of this, the necessity, while urgent, still doesn’t appear. dr. gilfoil trusted his brother, criminal though he was, to return to his cell in four weeks and finish his sentence. the exchange of prisoners then was to be made in the same manner. that the criminal brother did not return, as he agreed, but that dr. gilfoil was loyal to him even then and lived up to the lie, can only reflect credit upon dr. gilfoil for a self sacrifice which is almost beyond us prosaic people of this day.”

“i did it because —” dr. gilfoil began hoarsely, his voice quivering with emotion. it was the first time he had spoken.

“it doesn’t matter why you did it,” interrupted the thinking machine. “you did it for love of a brother, and he betrayed you — betrayed you to the point of his taking possession of your house while maudlin from drink, to the point of striking your wife like the coward he is, and of making a temporary prisoner of mr. hatch here, who had gone to your home to investigate. it is due to mr. hatch’s personal courage that your wife is freed from him — she was practically a prisoner — and that he is now in his cell again.”

dr. gilfoil’s face went pallid for an instant, and he staggered to his feet, with lips tightly pressed together, fighting back an emotion which nearly overwhelmed him. after a moment came a strange softening of his features, and he stood staring out the window into the prison yard with upraised eyes.

“that’s all of it,” said the scientist, after a moment. “i don’t think, mr. warden, that justice would demand the imprisonment of this man. i believe it would be far better to let the matter remain just between ourselves. it will not happen again, and —”

“but it was a crime,” interrupted the warden.

“technically, yes,” admitted the thinking machine; “but we can overlook even a crime, if it does no harm, and if it is inspired by the motive which prompted this one. think of it for a moment in that light.”

there was a long silence in the little office. the thinking machine sat with upturned eyes and fingers pressed tip to tip; dr. gilfoil’s eyes roved from the drawn, inscrutable face of the scientist to the warden; hatch’s brow was furrowed with wrinkles of perplexity.

“how did you find out about this escape first?” asked the reporter curiously.

“i knew philip gilfoil had escaped, because i saw him,” replied the thinking machine tersely. “he came to my place, evidently to kill me. i was in my laboratory. he came up behind me to strike me down. i glanced into a mirror above my work table, saw him, and tried to avoid the blow. it caught me in the back of the head, and i fell unconscious. martha made some noise outside which must have frightened gilfoil, for he fled. the front door locked behind him — it’s a spring lock. but i had recognized the escaped prisoner perfectly — i never forget faces — and i knew he had the motive to kill me because i had been instrumental in sending him here.

“i told you merely that gilfoil had escaped and sent you here to inquire. afterward i came myself, because i knew philip gilfoil was not in that cell. i found out many additional facts, among them a sudden change for the better in the prisoner’s behavior, which confirmed my knowledge that it was philip gilfoil who had attacked me. i sought to surprise dr. gilfoil here into a betrayal of identity by a visit to his cell at night. but his loyalty to his brother and his perfect self possession enabled him to play the role. he recognized me as he recognized you, mr. hatch, because we can imagine that philip gilfoil had been careful in his plans and had instructed him to look out for us.

“everything else came from the record book. this gave me philip gilfoil’s pedigree, mentioned phineas gilfoil, without stating his vocation, and gave a clue to his place of residence. you followed up that end, mr. hatch, while i called on dr. heindell who had treated the prisoner for a bad throat. he informed me that there was nothing at all the matter with the prisoner’s throat, so a plain problem in addition brought me a definite knowledge of what had happened. in conclusion, i may say that dr. gilfoil planned only a four weeks’ stay here. i know that because you told me he had gone on a four weeks’ vacation.”

the minister’s eyes again settled on the face of the warden. that official had been turning the matter over in his mind, evidently at length, as he listened. finally he spoke.

“you had better go back to the cell, dr. gilfoil,” he said respectfully, “and change clothing with your brother. you couldn’t wear that prison suit in the street safely.”