richard duvall had had charge of many unusual and intricate cases, in the past, and he prided himself upon the fact that he had handled them with skill and discretion, and that the results which had followed had been both quick and decisive. but in all his career he had not, so far as he could remember, ever felt quite so chagrined, as he did when he threw open the door of the cab and found that the woman he had left there had disappeared.

the fault was his, he knew that well—entirely and unmistakably his. this woman was evidently far more clever, more subtle than he had imagined. he realized now that she had in all probability not taken the drug he had given her in the dressing room of the theater, that she had seen his effort to examine the contents of her handbag, that her weakness, her call for a stimulant of some sort had been but clever acting, and that she had purposely sent him into the drug store in order that she might escape. he blamed himself, utterly and completely, for his amazing stupidity in not realizing that the woman, instead of ordering the cabman to drive away, had only to slip out through the door on the opposite side of the vehicle, and vanish in the darkness.

and this she had quite evidently done. the door of the cab opposite him stood open. no doubt she had purposely refrained from closing it, fearing that the click of the lock might attract the driver's attention. the latter with his eyes following duvall, as the detective entered the store, had remained serenely unconscious of his passenger's movements, her clever escape.

at least three or four minutes had elapsed. duvall glanced up and down the street, but no sight of the vanished woman greeted his anxious gaze. she had had ample time to reach the next corner, and disappear in the darkness. thoughts of pursuit entered his mind, but he realized at once the fruitlessness of such an attempt. his captive might have fled east or west, at either of the streets north or south of where he stood. or she might have entered some restaurant, some motion picture house, or other convenient doorway along the avenue. she might even have boarded a sixth avenue car, or hailed a passing cab. he looked up at the chauffeur, who still sat at his steering wheel, totally unaware of the flight of one of his passengers.

"the woman has gone," duvall exclaimed, nodding toward the vacant cab.

the man turned in complete surprise. he seemed scarcely able to credit the evidence of his senses.

"i—why sir—she was here just a moment ago, sir," he gasped, gazing into the interior of the cab as though he expected its recent occupant to suddenly materialize in the flesh.

"she got out on the other side, while i was in the store," duvall remarked, shortly, then taking an electric searchlight from his pocket, made a thorough examination of the interior of the cab. he scarcely expected to find anything, although it flashed through his mind that the woman, in her hurry to escape, might have left her bag, her gloves, or something that might afford him a clue to her identity.

at first he saw nothing. then, as his eyes became more accustomed to the brilliant glare of the electric torch, he observed a bit of white cardboard lying on the floor. it looked like a visiting card, and he snatched it up, devoutly hoping that it had fallen from the woman's bag during the attempt he had made to rifle it.

under the light of his pocket lamp he made a quick examination of his find. it proved a lamentable disappointment. it was in fact a visiting card, or to be more correct, the torn half of one, but what was engraved upon it afforded him not the least clue to either the identity or the address of the woman he sought. on the first line were the words, "miss mar"—then came the torn edge of the card. on the second line there was but the figure 1, and then the break.

was the name so tantalizingly suggested by the letters before him "miss mary" something or other? or "miss margaret?" or was it "miss martin," or "miss marvin," or "miss marbury," or any one of a score of other names beginning with the letters "mar?" and what was the missing address? what numbers followed the figure 1, on that part of the card that had been torn off? and what was the name of the street? he realized at once that while what he had found might, under certain circumstances, act as a suggestion, it would not serve to get him very far, unless reinforced by other and more definite evidence. he thought for a moment of securing from mr. baker a list of the women employees of the studio. it was true, he remembered, that his prisoner had not been seated in that particular section of the house reserved for the company's employees, but that might have readily come from the fact that the section was fully occupied when she arrived. then, as more names beginning with "mar" occurred to him, the futility of the idea became apparent. apart from any possible number of marys, and margarets there were martha, maria, marcia, marian, marcella—others perhaps. of course he would be able to recognize the woman, if he saw her, but she would be too clever to return to her place in the studio the following day, if by any chance she worked there, knowing, as she must inevitably know, that she would be identified at once.

still, there was of course the chance that mr. baker might have recognized her. he presumably knew all the employees of his company by sight. duvall got into the cab with a mortifying sense of having made a very foolish blunder, and directed the cabman to drive him back to the grand theater.

mr. baker was waiting in the lobby when the detective arrived, and at a nod from the latter the two men retired to the dressing room in which they had had their previous consultation. the moving picture man's face was eager, expectant, as he waited for duvall to speak, and the latter felt his chagrin increase by the moment.

when he had at last finished his account of the affair, mr. baker looked exceedingly grave.

"too bad—too bad," he muttered, "to have had her in our hands like that, and then, to lose her."

"did you ever see the woman before?" duvall questioned.

"no. of course she might be in our employ, but i doubt it, although i could not be expected to know by sight every girl who works in the plant. there are stenographers, film cutters and pasters, dozens of others, that i do not engage directly, and never see. let me look at the card."

duvall handed the torn bit of pasteboard to him.

"not much to go on," he said, quietly.

"no. not much."

"of course," the detective went on, "the evening has not been entirely wasted. we know the woman by sight, and that is a great deal. as for her name, i have made a careful study of this card, and assuming it to have been of the usual length in comparison to its width, the name following the 'miss,' if it was a first name, points to a very short one, such as mary, and not a long one, such as margaret."

"how do you make that out?"

"simply enough. the entire name would of course have been placed in the center of the card, which was, it appears, torn almost exactly in half. on the left-hand side, which we have in our possession, there are, in the word 'miss,' four letters, and in 'mar' three, or seven in all. we should correspondingly expect to find seven letters on the right or missing half of the card. but were the first name margaret, or marcella, which each contain eight letters, or five to be added to the 'mar' we already have, it would leave but two letters for the woman's last name, and names of that length, or rather shortness, are so rare as to be negligible. it is far more probable that we have but to add a 'y' to the 'mar,' or one letter, leaving six for the last name. this would give us 'miss mar-y gordon,' with the name evenly divided by the tear. or, if by chance, the first name is such a one as marian, containing six letters, we need add but the 'ian,' or three letters, to the left-hand side of our card, leaving us four letters for the last name. thus, miss marian kent. the full name on the card should have just fourteen letters, provided the card is, as i conclude, torn exactly in half."

"why do you conclude that?"

"because visiting cards of this sort are usually made in standard sizes. i happen to have a woman's card—miss morton's, in fact, in my pocket. its width is the same as that of the torn card, and if the latter was of the same length, you can readily see that it was torn exactly in half." he took a card from his wallet and laid the torn bit of pasteboard upon it. their widths were identical. the whole card was just twice the length of the torn one.

"that is a most interesting deduction," baker exclaimed. "what use can we make of it?"

"i will tell you. you have your car here, have you not?"

"yes."

"then i suggest that we run down to the studio at once, get your list of employees, examine the name of every woman upon it, and see if we cannot find one of fourteen letters, including the 'miss,' of which the first name begins with 'mar.' the chances are that we will be able to locate the name immediately."

"yes," mr. baker exclaimed, rising in some excitement, "but, as you have before said, the woman, if she works for us, will not dare to appear in the morning, for fear that she will be recognized at once."

"that is true, but you will no doubt have on your books her home address. if we hurry, we can get there and back by midnight, and we may be able to place our hands on the woman before she can have time to escape."

mr. baker reached the door in two steps.

"come along," he said. "we'll burn up the roads."

the two men said little, during their long ride. when they reached the entrance to the dark and silent studio building, only the night watchman appeared to greet them.

inside the building, however, there were more signs of life. some stage carpenters were busy, working overtime on a piece of scenery. in the developing and drying departments were also signs of activity. mr. baker led the way to his office. "it happens," he said, "that as i am obliged to o. k. the payroll each week, i have a list of our employees in my desk." as he spoke, he took his keys, opened a drawer, and drew out a small red book.

"here is the list, with the home addresses," he said. "how shall we go to work?"

"read me all the women's names, in which the first name begins with 'mar,'" duvall said. "i will put them down on a sheet of paper." he drew a pad toward him, took out his pencil, and the two set to work.

when they had at last reached the end of the book, both duvall and mr. baker were surprised to find that the names they had picked out were so few. in all there were but eight, as follows:

miss mary sollenberger,

miss mary green,

miss margaret schwartz,

miss maria rosenheim,

miss martha simmons,

miss marcia ford,

miss marian greenberg,

miss mary king.

duvall ran his pencil down the list of names. "there is but one that fulfills the requirements," he announced. "the sixth name, that of miss marcia ford, contains in all fourteen letters. none of the others do. two, those of miss king and miss green, come the nearest. miss king's full name contains twelve letters, miss green's, thirteen. any one of the three might be the one we seek."

"i can answer for miss king at once," said mr. baker, quietly. "she is my stenographer, and most certainly not the woman who was in the theater to-night."

"that leaves then, miss green and miss ford. what do they do, and what are their addresses?"

mr. baker referred to his book.

"miss green is a telephone operator. her address is given here as 310 gold street, brooklyn. miss ford is a film cutter, and lives at 122 west 9th street, new york."

"neither sounds particularly promising," duvall remarked, with a frown.

"no. but of course we are assuming that the woman in question works in the studio. if she does not, our whole fabric falls to pieces." duvall took the torn piece of card from his pocket and glanced at it.

"the address given here begins with the number 1," he said, significantly. "it may be that miss marcia ford, of 122 west ninth street, is the woman we are looking for, although i confess i should have suspected some rival motion picture star, rather than a film cutter."

"by george, i forgot the fact that the card had an address on it," baker exclaimed. "i think we had better look up miss ford at once."

"i agree with you," duvall said. a few moments later they were driving at top speed back toward new york.

it was five minutes to twelve when they reached the corner of fifth avenue and ninth street and turned west. duvall realized that they were following a very slim clue, but it seemed for the moment the only promising one they had.

the house, no. 122, proved to be a typical high stooped, brownstone boarding house of this section of the city. it was for the most part dark, although one or two of the upper windows showed lights.

accompanied by baker, duvall quickly mounted the steps and rang the bell. at first there was no answer, although they could hear the sound of the bell tinkling mournfully inside. a second summons brought no greater response. at the third, a woman's head appeared in one of the upper windows, and they heard a shrill and not over pleasant voice asking them what they wanted.

"i have an important message for miss marcia ford," duvall replied pleasantly. "i must see her at once."

"miss ford moved away from here three months ago," the woman snapped.

"will you please give me her present address?" the detective exclaimed, somewhat taken aback.

"i don't know it. she didn't say where she was going. good night!" a moment later the window above them was closed with a slam.

the two men stood staring at each other in the utmost disappointment. they had expected a more favorable outcome of their expedition.

"how long has she been with you?" duvall asked, turning to his companion.

"i don't know. certainly over three months, or we shouldn't have this address on our books. i suppose, when she changed it, she omitted to notify us. what are we going to do now?"

"there isn't anything we can do, until morning. if miss marcia ford reports for work to-morrow, and you see that she is the woman who fainted in the theater to-night, have her arrested at once. if she doesn't report for work, at least we shall know that she is the woman we are after."

"that isn't much consolation," mr. baker grumbled.

"i don't agree with you. having the woman's name, knowing her appearance, we are certain to catch her, sooner or later. and in the meanwhile, i do not think that she will attempt anything further so far as miss morton is concerned. we are too close on her trail, for that."

"i hope you are right," said the motion picture man. "well, i guess i'll go along home. i'll be at the studio first thing in the morning, however, and i suppose you will be there too."

"by all means. i am most curious to see whether our reasoning to-night has been correct."

"shall i take you to your hotel in my car?"

"no, thanks. i'll take a taxi. good night."

"good night."

a few moments later, duvall was speeding up fifth avenue, his brain still puzzling over the curious contradictions which the events of the night had developed. on one point he felt secure, however. he was certain that the woman who had so narrowly escaped him earlier in the evening would not soon again attempt anything against ruth morton.

arrived at his hotel, he asked for his key. the man behind the desk, with a queer look, handed him along with it a slip of paper. on it was written: "mrs. bradley wishes mr. john bradley to come to her room at the moment he returns."

"when was this message left?" the detective asked.

"oh—nearly two hours ago. the time is stamped on the back of it, sir."

duvall turned the card over, and saw from the stamp on the other side that mrs. morton had sent for him at half past ten.

"the message was phoned down by the lady herself," the clerk added, by way of explanation.

duvall went up in the elevator, and a few moments later, was knocking at the door of mrs. morton's suite.

the latter herself appeared in the doorway. she was pale and agitated. "come in, mr. duvall," she said.

the detective entered, closing the door behind him.

"what is wrong, mrs. morton?" he asked.

"there has been another warning—a dreadful one," the older woman exclaimed, her voice trembling. "it came a little after ten."

"what was it?" duvall's voice was almost as strained as that of the woman before him. her words came to him as a complete surprise. had all the work of the evening, then, been wasted?

"at a little after ten," mrs. morton said slowly, "i sent my maid nora out for some medicine for my daughter. she went to a drug store some three blocks away. as she returned to the hotel, she saw a young woman standing near the entrance, apparently watching those who went in and out. as soon as the maid came up to the doorway, the woman stepped up to her, and thrusting a package into her hands, said quickly, 'give this to miss ruth morton. it is from the studio.' then she walked away at once.

"nora, as she tells me, did not know just what to do. you will remember that while she realizes from our presence here under an assumed name, that something is wrong, she knows little or nothing of the circumstances surrounding ruth's terrible persecution. hence she foolishly took both the medicine and the package the woman had given her, to my daughter."

"yes—yes—go on," duvall exclaimed, seeing mrs. morton pause.

"ruth opened them both. i was in the next room at the moment. suddenly i heard a cry, and on rushing in, found her standing in the center of the room, holding a small bottle in one hand, and staring at it in the utmost consternation. in her other hand was a sheet of paper, which, as i subsequently found, had been wrapped around the bottle, inside the outer brown-paper cover.

"the bottle was labeled 'carbolic acid.' here is the sheet of paper." mrs. morton, with trembling fingers, extended a half sheet of note-paper toward the detective.

duvall took it and read the typewritten words upon it.

"we gave you thirty days. now we give you seven. drink this, and save yourself from a horrible fate." the death's head signature ended the message. "ruth has been very ill ever since," mrs. morton added drearily. "if she is not better in the morning, i shall call in a doctor. she felt herself absolutely safe, here, and was recovering her cheerfulness. now all her fears have returned with redoubled force. i am terribly worried about her—terribly worried." taking out her handkerchief, the poor woman wiped the tears from her eyes. "how could these people have known we were here?" she whispered, in an awed voice. "it seems like the work of fiends."

there was little that the detective could say in reply. even to his sober judgment, there came a suggestion of the uncanny, the supernatural. the woman in the cab had escaped at half past nine, presumably quite ignorant of the location of mrs. morton's retreat. half an hour later, the campaign of intimidation was renewed with greater vigor than before.

"i'm afraid, mrs. morton," he said, "that it will be necessary for you to remain with your daughter every minute of the time, for a day or two. by then, i am convinced that we shall have laid our hands on the guilty parties. good night."

duvall rose very early the following morning, and drove at once to the studio, but early as he was, mr. baker was there before him.

the latter was seated in his office, poring over a mass of reports, when duvall entered. he glanced up, rose, shook hands nervously, then motioned to a chair.

"nothing new yet," he said. "my stenographer, miss king, is here. neither miss green nor miss ford have yet arrived, but it is still a little early. miss king came before her usual time, as she had some reports to get out that she could not complete last night. we have at least fifteen minutes to wait."

duvall told him to proceed with his work, and drawing a newspaper from his pocket, made an effort to interest himself in it. in this, however, he was not very successful. time after time his mind would wander from the printed sheet before him to the strange events of the night before. the thing that puzzled him most was, how did the persecutors of miss morton discover her new address so soon? was the woman who had handed the package to nora, the maid, the same one that had vanished from the cab? he remembered that it had been about nine o'clock when they left the grand theater, and perhaps half-past when he had gone into the drug store in sixth avenue to get the aromatic spirits of ammonia. had the woman gone directly from the cab to the hotel? she must have done so, without much loss of time, in order to reach there by ten o'clock. how had she known the address? he knew very well that he had given it to the cabman, when they started away from the theater. had the supposedly fainting woman overheard his words? if she had, and had so promptly acted upon them, she was far more clever and determined than her appearance would seem to warrant. he revolved the matter endlessly in his mind, waiting for mr. baker to announce that the time had come, when miss ford's or miss green's arrival or non-arrival would indicate which of the two, if either, was the woman they sought.

suddenly the bell of the telephone on mr. baker's desk ran sharply. he answered it, then turned to duvall.

"miss green, the telephone operator, is at her desk," he said. "would you like to take a look at her?"

"yes." the detective arose, and followed mr. baker into the corridor. the switchboard of the building was located at the end of the hall, in a small bare room. when they reached it, mr. baker spoke to a dark-haired, rather stout, woman who sat at the desk.

"miss green," he said, "if any calls come in for mr. duvall, he will be in my office." then he went back along the corridor.

"she certainly isn't the woman we are after," he remarked to duvall, as soon as they were out of earshot.

"no. it must be miss ford," the detective replied.

"suppose we go to the developing and finishing department," baker suggested. "it is time all our people were on hand. mr. emmett, who is in charge there, can tell us about miss ford."

they crossed to the other side of the building, and entered a small office. a bald-headed man sat at a littered desk.

"mr. emmett," baker said, "shake hands with mr. duvall. he is looking for a young woman in the finishing department. miss marcia ford. has she come in yet?"

"no," replied the bald-headed man, gravely shaking hands. "she is not here this morning. it is rather surprising, too, for she usually is on time."

"what sort of a looking woman is she?" duvall inquired.

"oh—a rather insignificant looking girl of about twenty-five. small, slender, not very prepossessing, but clever—enormously clever. one of the best film cutters we have. i should be sorry to lose her."

"light blue eyes, and light hair," duvall questioned. "and a thin, rather cruel mouth?"

"exactly. but why? has she gotten into any trouble?"

"no—i hope not. i merely wanted to see her."

"well—of course she may show up later, although as i say she has usually been very punctual. i shouldn't be surprised if she is sick. she's been acting rather peculiarly, the past few days."

"how so?" asked duvall, quickly.

"i can't say—exactly. i got the impression from her manner that she was nervous, excited, out of sorts. merely an impression, but such things count."

"telephone me, emmett," mr. baker said, "if she comes in during the next hour. come along, mr. duvall, you can wait in my office."

they returned to the other side of the immense building, and duvall sat down to wait. he felt sure that they were on the right track, and was impatient to get back to new york and try to locate the missing woman. the description given by mr. emmett left little doubt in his mind that she and miss marcia ford were one and the same. he sat in mr. baker's office, reading the paper, waiting anxiously for the hour the latter had specified to pass.

after what seemed an interminable wait, mr. baker glanced at his watch, then rose.

"it is ten o'clock, mr. duvall," he announced. "miss ford has not come, or mr. emmett would have notified me. i do not see that there is anything further to be accomplished here."

as he spoke, the telephone bell rang sharply. mr. baker picked up the receiver, listened intently for a few moments, then slammed the receiver back upon the hook.

"hell!" he ejaculated softly.

"what is it?" duvall asked.

"miss ford has just reported for work!"