Muller's lodgings consisted of two large rooms, really much too large for a lone man who was at home so little. But Muller had engaged them at first sight, for the apartment possessed one qualification which was absolutely necessary for him. Its situation and the arrangement of its doors made it possible for him to enter and leave his rooms without being seen either by his own landlady or by the other lodgers in the house. The little apartment was on the ground floor, and Muller's own rooms had a separate entrance opening on to the main corridor almost immediately behind the door. Nine times out of ten, he could come and go without being seen by any one in the house. To-day was the first time, however, that Muller had had occasion to try this particular qualification of his new lodgings.
He opened the street door and slipped into his own room without having seen or been seen by any one.
Fifteen minutes later he left the apartment again, but left it such a changed man that nobody who had seen him go in would have recognised him. Before he came out, however, he looked about carefully to see whether there was any one in sight He came out unseen and was just closing the main door behind him, when he met the janitress.
"Were you looking for anybody in the house?" said the woman, glancing sharply at the stranger, who answered in a slightly veiled voice: "No, I made a mistake in the number. The place I am looking for is two houses further down."He walked down the street and the woman looked after him until she saw him turn into the doorway of the second house. Then she went into her own rooms. The house Muller entered happened to be a corner house with an entrance on the other street, through which the detective passed and went on his way. He was quite satisfied with the security of his disguise, for the woman who knew him well had not recognised him at all. If his own janitress did not know him, the people in the Thorne house would never imagine it was he.
And indeed Muller was entirely changed. In actuality small and thin, with sparse brown hair and smooth shaven face, he was now an inch or two taller and very much stouter. He wore thick curly blond hair, a little pointed blond beard and moustache. His eyes were hidden by heavy-rimmed spectacles.
It was just half-past five when he rang the bell at the entrance gate to the Thorne property. He had spent the intervening time in the caf? as he was in no hurry to enter the house. Franz came down the path and opened the door. "'What do you want?" he asked.
"I come from Siemens & Halske; I was to ask whether the other man - ""Has been here already?" interrupted Franz, adding in an irritated tone, "No, he hasn't been here at all.""Well, I guess he didn't get through at the other place in time.
I'll see what the trouble is," said the stranger, whom Franz naturally supposed to be the electrician, lie opened the gate and asked the other to come in, leading him into the house. Under a cloudy sky the day was fading rapidly. Muller knew that it would not occur to the real electrician to begin any work as late as this, and that he was perfectly safe in the examination he wanted to make.
"Well, what's the trouble here? Why did you write to our firm?"asked the supposed electrician.
"The wires must cross somewhere, or there's something wrong with the bells. When the housekeeper touches the button in her room to ring for the cook or the upstairs girl, the bell rings in Mr. Thorne's room. It starts ringing and it keeps up with a deuce of a noise.
Fortunately the family are away."
"Well, we'll fix it all right for you. First of all I want to look at the button in the housekeeper's room.""I'll take you up there," said Franz.
They walked through the wide corridor, then turned into a shorter, darker hall and went up a narrow winding stairway. Franz halted before a door in the second story. It was the last of the three doors in the hall." Muller took off his hat as the door opened and murmured a "good-evening.""There's no one there; Mrs. Bernaner's out."
"Has she gone away, too?" asked the electrician hastily.
Franz did not notice that there was a slight change in the stranger's voice at this question, and he answered calmly as ever: "Oh, no;she's just driven to town. T think she went to see the doctor who lives quite a distance away. She hasn't been feeling at all well.
She took a cab to-day. I told her she ought to, as she wasn't well enough to go by the tram. She ought to be home any moment now.""Well, I'll hurry up with the job so that I'll be out of the way when the lady comes," said Muller, as Franz led him to the misbehaving bell.
It was in the wall immediately above a large table which filled the window niche so completely that there was but scant space left for the comfortable armchair that stood in front of it. The window was open and Muller leaned out, looking down at the garden below.
"What a fine old garden!" he exclaimed aloud. To himself he said:
"This is the last window in the left wing. It is the window where Johann Knoll saw the red light."And when he turned back into the room again he found the source of this light right at his hand on the handsome old table at which Mrs.
Bernauer evidently spent many of her hours. A row of books stood against the wall, framing the back of the table. Well-worn volumes of the classics among them gave proof that the one-time nurse was a woman of education. A sewing basket and neat piles of house linen, awaiting repairs, covered a large part of the table-top, and beside them stood a gracefully shaped lamp, covered by a shade of soft red silk.
It took Muller but a few seconds to see all this. Then he set about his investigation of the electric button. He unscrewed the plate and examined the wires meeting under it. While doing so he cast another glance at the table and saw a letter lying there, an open letter half out of its envelope. This envelope was of unusual shape, long and narrow, and the paper was heavy and high-glossed.
