Seldom has a young man spent a more desolate afternoon than Aubrey on that Sunday. His only consolation was that twenty minutes after he had left the bookshop he saw a taxi drive up (he was then sitting gloomily at his bedroom window) and Titania enter it and drive away. He supposed that she had gone to join the party in Larchmont, and was glad to know that she was out of what he now called the war zone. For the first time on record, O. Henry failed to solace him. His pipe tasted bitter and brackish. He was eager to know what Weintraub was doing, but did not dare make any investigations in broad daylight. His idea was to wait until dark. Observing the Sabbath calm of the streets, and the pageant of baby carriages wheeling toward Thackeray Boulevard, he wondered again whether he had thrown away this girl's friendship for a merely imaginary suspicion.

At last he could endure his cramped bedroom no longer. Downstairs someone was dolefully playing a flute, most horrible of all tortures to tightened nerves. While her lodgers were at church the tireless Mrs. Schiller was doing a little housecleaning: he could hear the monotonous rasp of a carpet-sweeper passing back and forth in an adjoining room. He creaked irritably downstairs, and heard the usual splashing behind the bathroom door. In the frame of the hall mirror he saw a pencilled note: Will Mrs. Smith please call Tarkington 1565, it said. Unreasonably annoyed, he tore a piece of paper out of his notebook and wrote on it Will Mrs. Smith please call Bath 4200. Mounting to the second floor he tapped on the bathroom door. "Don't come in!" cried an agitated female voice. He thrust the memorandum under the door, and left the house.

Walking the windy paths of Prospect Park he condemned himself to relentless self-scrutiny. "I've damned myself forever with her," he groaned, "unless I can prove something." The vision of Titania's face silhouetted against the shelves of books came maddeningly to his mind. "I was going to have such a good time, and you've spoilt it all!" With what angry conviction she had said: "I never saw a man like you before — and I've seen a good many!"

Even in his disturbance of soul the familiar jargon of his profession came naturally to utterance. "At least she admits I'm different," he said dolefully. He remembered the first item in the Grey-Matter Code, a neat little booklet issued by his employers for the information of their representatives:

Business is built upon Confidence. Before you can sell Grey-Matter Service to a Client, you must sell Yourself.

"How am I going to sell myself to her?" he wondered. "I've simply got to deliver, that's all. I've got to give her service that's different. If I fall down on this, she'll never speak to me again. Not only that, the firm will lose the old man's account. It's simply unthinkable."

Nevertheless, he thought about it a good deal, stimulated from time to time as in the course of his walk (which led him out toward the faubourgs of Flatbush) he passed long vistas of signboards, which he imagined placarded with vivid lithographs in behalf of the Chapman prunes. "Adam and Eve Ate Prunes On Their Honeymoon" was a slogan that flashed into his head, and he imagined a magnificent painting illustrating this text. Thus, in hours of stress, do all men turn for comfort to their chosen art. The poet, battered by fate, heals himself in the niceties of rhyme. The prohibitionist can weather the blackest melancholia by meditating the contortions of other people's abstinence. The most embittered citizen of Detroit will never perish by his own hand while he has an automobile to tinker.

Aubrey walked many miles, gradually throwing his despair to the winds. The bright spirits of Orison Swett Marden and Ralph Waldo Trine, Dioscuri of Good Cheer, seemed to be with him reminding him that nothing is impossible. In a small restaurant he found sausages, griddle cakes and syrup. When he got back to Gissing Street it was dark, and he girded his soul for further endeavour.

About nine o'clock he walked up the alley. He had left his overcoat in his room at Mrs. Schiller's and also the Cromwell bookcover — having taken the precaution, however, to copy the inscriptions into his pocket memorandum-book. He noticed lights in the rear of the bookshop, and concluded that the Mifflins and their employee had got home safely. Arrived at the back of Weintraub's pharmacy, he studied the contours of the building carefully.

The drug store lay, as we have explained before, at the corner of Gissing Street and Wordsworth Avenue, just where the Elevated railway swings in a long curve. The course of this curve brought the scaffolding of the viaduct out over the back roof of the building, and this fact had impressed itself on Aubrey's observant eye the day before. The front of the drug store stood three storeys, but in the rear it dropped to two, with a flat roof over the hinder portion. Two windows looked out upon this roof. Weintraub's back yard opened onto the alley, but the gate, he found, was locked. The fence would not be hard to scale, but he hesitated to make so direct an approach.

He ascended the stairs of the "L" station, on the near side, and paying a nickel passed through a turnstile onto the platform. Waiting until just after a train had left, and the long, windy sweep of planking was solitary, he dropped onto the narrow footway that runs beside the track. This required watchful walking, for the charged third rail was very near, but hugging the outer side of the path he proceeded without trouble. Every fifteen feet or so a girder ran sideways from the track, resting upon an upright from the street below. The fourth of these overhung the back corner of Weintraub's house, and he crawled cautiously along it. People were passing on the pavement underneath, and he greatly feared being discovered. But he reached the end of the beam without mishap. From here a drop of about twelve feet would bring him onto Weintraub's back roof. For a moment he reflected that, once down there, it would be impossible to return the same way. However, he decided to risk it. Where he was, with his legs swinging astride the girder, he was in serious danger of attracting attention.

He would have given a great deal, just then, to have his overcoat with him, for by lowering it first he could have jumped onto it and muffled the noise of his fall. He took off his coat and carefully dropped it on the corner of the roof. Then cannily waiting until a train passed overhead, drowning all other sounds with its roar, he lowered himself as far as he could hang by his hands, and let go.

For some minutes he lay prone on the tin roof, and during that time a number of distressing ideas occurred to him. If he really expected to get into Weintraub's house, why had he not laid his plans more carefully? Why (for instance) had he not made some attempt to find out how many there were in the household? Why had he not arranged with one of his friends to call Weintraub to the telephone at a given moment, so that he could be more sure of making an entry unnoticed? And what did he expect to see or do if he got inside the house? He found no answer to any of these questions.

It was unpleasantly cold, and he was glad to slip his coat on again. The small revolver was still in his hip pocket. Another thought occurred to him — that he should have provided himself with tennis shoes. However, it was some comfort to know that rubber heels of a nationally advertised brand were under him. He crawled quietly up to the sill of one of the windows. It was closed, and the room inside was dark. A blind was pulled most of the way down, leaving a gap of about four inches. Peeping cautiously over the sill, he could see farther inside the house a brightly lit door and a passageway.

"One thing I've got to look out for," he thought, "is children. There are bound to be some — who ever heard of a German without offspring? If I wake them, they'll bawl. This room is very likely a nursery, as it's on the southeastern side. Also, the window is shut tight, which is probably the German idea of bedroom ventilation."

His guess may not have been a bad one, for after his eyes became accustomed to the dimness of the room he thought he could perceive two cot beds. He then crawled over to the other window. Here the blind was pulled down flush with the bottom of the sash. Trying the window very cautiously, he found it locked. Not knowing just what to do, he returned to the first window, and lay there peering in. The sill was just high enough above the roof level to make it necessary to raise himself a little on his hands to see inside, and the position was very trying. Moreover, the tin roof had a tendency to crumple noisily when he moved. He lay for some time, shivering in the chill, and wondering whether it would be safe to light a pipe.

"There's another thing I'd better look out for," he thought, "and that's a dog. Who ever heard of a German without a dachshund?"

He had watched the lighted doorway for a long while without seeing anything, and was beginning to think he was losing time to no profit when a stout and not ill-natured looking woman appeared in the hallway. She came into the room he was studying, and closed the door. She switched on the light, and to his horror began to disrobe. This was not what he had counted on at all, and he retreated rapidly. It was plain that nothing was to be gained where he was. He sat timidly at one edge of the roof and wondered what to do next.

As he sat there, the back door opened almost directly below him, and he heard the clang of a garbage can set out by the stoop. The door stood open for perhaps half a minute, and he heard a male voice — Weintraub's, he thought — speaking in German. For the first time in his life he yearned for the society of his German instructor at college, and also wondered — in the rapid irrelevance of thought — what that worthy man was now doing to earn a living. In a rather long and poorly lubricated sentence, heavily verbed at the end, he distinguished one phrase that seemed important. "Nach Philadelphia gehen" — "Go to Philadelphia."

Did that refer to Mifflin? he wondered.

The door closed again. Leaning over the rain-gutter, he saw the light go out in the kitchen. He tried to look through the upper portion of the window just below him, but leaning out too far, the tin spout gave beneath his hands. Without knowing just how he did it, he slithered down the side of the wall, and found his feet on a window-sill. His hands still clung to the tin gutter above. He made haste to climb down from his position, and found himself outside the back door. He had managed the descent rather more quietly than if it had been carefully planned. But he was badly startled, and retreated to the bottom of the yard to see if he had aroused notice.

A wait of several minutes brought no alarm, and he plucked up courage. On the inner side of the house — away from Wordsworth Avenue — a narrow paved passage led to an outside cellar-way with old-fashioned slanting doors. He reconnoitred this warily. A bright light was shining from a window in this alley. He crept below it on hands and knees fearing to look in until he had investigated a little. He found that one flap of the cellar door was open, and poked his nose into the aperture. All was dark below, but a strong, damp stench of paints and chemicals arose. He sniffed gingerly. "I suppose he stores drugs down there," he thought.

Very carefully he crawled back, on hands and knees, toward the lighted window. Lifting his head a few inches at a time, finally he got his eyes above the level of the sill. To his disappointment he found the lower half of the window frosted. As he knelt there, a pipe set in the wall suddenly vomited liquid which gushed out upon his knees. He sniffed it, and again smelled a strong aroma of acids. With great care, leaning against the brick wall of the house, he rose to his feet and peeped through the upper half of the pane.

It seemed to be the room where prescriptions were compounded. As it was empty, he allowed himself a hasty survey. All manner of bottles were ranged along the walls; there was a high counter with scales, a desk, and a sink. At the back he could see the bamboo curtain which he remembered having noticed from the shop. The whole place was in the utmost disorder: mortars, glass beakers, a typewriter, cabinets of labels, dusty piles of old prescriptions strung on filing hooks, papers of pills and capsules, all strewn in an indescribable litter. Some infusion was heating in a glass bowl propped on a tripod over a blue gas flame. Aubrey noticed particularly a heap of old books several feet high piled carelessly at one end of the counter.

Looking more carefully, he saw that what he had taken for a mirror over the prescription counter was an aperture looking into the shop. Through this he could see Weintraub, behind the cigar case, waiting upon some belated customer with his shop-worn air of affability. The visitor departed, and Weintraub locked the door after him and pulled down the blinds. Then he returned toward the prescription room, and Aubrey ducked out of view.

Presently he risked looking again, and was just in time to see a curious sight. The druggist was bending over the counter, pouring some liquid into a glass vessel. His face was directly under a hanging bulb, and Aubrey was amazed at the transformation. The apparently genial apothecary of cigar stand and soda fountain was gone. He saw instead a heavy, cruel, jowlish face, with eyelids hooded down over the eyes, and a square thrusting chin buttressed on a mass of jaw and suetty cheek that glistened with an oily shimmer. The jaw quivered a little as though with some intense suppressed emotion. The man was completely absorbed in his task. The thick lower lip lapped upward over the mouth. On the cheekbone was a deep red scar. Aubrey felt a pang of fascinated amazement at the gross energy and power of that abominable relentless mask.

"So this is the harmless old thing!" he thought.

Just then the bamboo curtain parted, and the woman whom he had seen upstairs appeared. Forgetting his own situation, Aubrey still stared. She wore a faded dressing gown and her hair was braided as though for the night. She looked frightened, and must have spoken, for Aubrey saw her lips move. The man remained bent over his counter until the last drops of liquid had run out. His jaw tightened, he straightened suddenly and took one step toward her, with outstretched hand imperiously pointed. Aubrey could see his face plainly: it had a savagery more than bestial. The woman's face, which had borne a timid, pleading expression, appealed in vain against that fierce gesture. She turned and vanished. Aubrey saw the druggist's pointing finger tremble. Again he ducked out of sight. "That man's face would be lonely in a crowd," he said to himself. "And I used to think the movies exaggerated things. Say, he ought to play opposite Theda Bara."

He lay at full length in the paved alley and thought that a little acquaintance with Weintraub would go a long way. Then the light in the window above him went out, and he gathered himself together for quick motion if necessary. Perhaps the man would come out to close the cellar door —

The thought was in his mind when a light flashed on farther down the passage, between him and the kitchen. It came from a small barred window on the ground level. Evidently the druggist had gone down into the cellar. Aubrey crawled silently along toward the yard. Reaching the lit pane he lay against the wall and looked in.

The window was too grimed for him to see clearly, but what he could make out had the appearance of a chemical laboratory and machine shop combined. A long work bench was lit by several electrics. On it he saw glass vials of odd shapes, and a medley of tools. Sheets of tin, lengths of lead pipe, gas burners, a vise, boilers and cylinders, tall jars of coloured fluids. He could hear a dull humming sound, which he surmised came from some sort of revolving tool which he could see was run by a belt from a motor. On trying to spy more clearly he found that what he had taken for dirt was a coat of whitewash which had been applied to the window on the inside, but the coating had worn away in one spot which gave him a loophole. What surprised him most was to spy the covers of a number of books strewn about the work table. One, he was ready to swear, was the Cromwell. He knew that bright blue cloth by this time.

For the second time that evening Aubrey wished for the presence of one of his former instructors. "I wish I had my old chemistry professor here," he thought. "I'd like to know what this bird is up to. I'd hate to swallow one of his prescriptions."

His teeth were chattering after the long exposure and he was wet through from lying in the little gutter that apparently drained off from the sink in Weintraub's prescription laboratory. He could not see what the druggist was doing in the cellar, for the man's broad back was turned toward him. He felt as though he had had quite enough thrills for one evening. Creeping along he found his way back to the yard, and stepped cautiously among the empty boxes with which it was strewn. An elevated train rumbled overhead, and he watched the brightly lighted cars swing by. While the train roared above him, he scrambled up the fence and dropped down into the alley.

"Well," he thought, "I'd give full-page space, preferred position, in the magazine Ben Franklin founded to the guy that'd tell me what's going on at this grand bolshevik headquarters. It looks to me as though they're getting ready to blow the Octagon Hotel off the map."

He found a little confectionery shop on Wordsworth Avenue that was still open, and went in for a cup of hot chocolate to warm himself. "The expense account on this business is going to be rather heavy," he said to himself. "I think I'll have to charge it up to the Daintybits account. Say, old Grey Matter gives service that's different, don't she! We not only keep Chapman's goods in the public eye, but we face all the horrors of Brooklyn to preserve his family from unlawful occasions. No, I don't like the company that bookseller runs with. If 'nach Philadelphia' is the word, I think I'll tag along. I guess it's off for Philadelphia in the morning!"