Mr. Gryce felt himself at a greater disadvantage in his attempt to solve the mystery of this affair than in any other which he had entered upon in years. First, the victim had been a solitary man, with no household save his man-of-all-work, the mute. Secondly, he had lived in a portion of the city where no neighbors were possible; and he had even lacked, as it now seemed, any very active friends. Though some hours had elapsed since his death had been noised abroad, no one had appeared at the door with inquiries or information. This seemed odd, considering that he had been for some months a marked figure in this quarter of the town. But, then, everything about this man was odd, nor would it have been in keeping with his surroundings and peculiar manner of living for him to have had the ordinary associations of men of his class.

This absence of the usual means of eliciting knowledge from the surrounding people, added to, rather than detracted from, the interest which Mr. Gryce was bound to feel in the case, and it was with a feeling of relief that a little before midnight he saw the army of reporters, medical men, officials, and such others as had followed in the coroner's wake, file out of the front door and leave him again, for a few hours at least, master of the situation.

For there were yet two points which he desired to settle before he took his own much-needed rest. The first occupied his immediate attention. Passing before a chair in the hall on which a small boy sat dozing, he roused him with the remark:

"Come, Jake, it's time to look lively. I want you to go with me to the exact place where that lady ran across you to-day."

The boy, half dead with sleep, looked around him for his hat.

"I'd like to see my mother first," he pleaded. "She must be done up about me. I never stayed away so long before."

"Your mother knows where you are. I sent a message to her hours ago. She gave a very good report of you, Jake; says you're an obedient lad and that you never have told her a falsehood."

"She's a good mother," the boy warmly declared. "I'd be as bad—as bad as my father was, if I did not treat her well." Here his hand fell on his cap, which he put on his head.

"I'm ready," said he.

Mr. Gryce at once led the way into the street.

The hour was late, and only certain portions of the city showed any real activity. Into one of these thoroughfares they presently came, and before the darkened window of one of the lesser shops paused, while Jake pointed out the two stuffed frogs engaged with miniature swords in mortal combat at which he had been looking when the lady came up and spoke to him.

Mr. Gryce eyed the boy rather than the frogs, though probably the former would have sworn that his attention had never left that miniature conflict.

"Was she a pretty lady?" he asked.

The boy scratched his head in some perplexity.

"She made me a good deal afraid of her," he said. "She had very splendid clothes; oh, gorgeous!" he cried, as if on this question there could be no doubt.

"And she was young, and carried a bunch of flowers, and seemed troubled? What! not young, and carried no flowers—and wasn't even anxious and trembling?"

The boy, who had been shaking his head, looked nonplussed.

"I think as she was what you might call troubled. But she wasn't crying, and when she spoke to me, she put more feeling into her grip than into her voice. She just dragged me to the drug-store, sir. If she hadn't given me money first, I should have wriggled away in spite of her. But I likes money, sir; I don't get too much of it."

Mr. Gryce by this time was moving on. "Not young," he repeated to himself. "Some old flame, then, of Mr. Adams; they're apt to be dangerous, very dangerous, more dangerous than the young ones."

In front of the drug-store he paused. "Show me where she stood while you went in."

The boy pointed out the identical spot. He seemed as eager as the detective.

"And was she standing there when you came out?"

"Oh, no, sir; she went away while I was inside."

"Did you see her go? Can you tell me whether she went up street or down?"

"I had one eye on her, sir; I was afraid she was coming into the shop after me, and my arm was too sore for me to want her to clinch hold on it again. So when she started to go, I took a step nearer, and saw her move toward the curbstone and hold up her hand. But it wasn't a car she was after, for none came by for several minutes."

The fold between Mr. Gryce's eyes perceptibly smoothed out.

"Then it was some cabman or hack-driver she hailed. Were there any empty coaches about that you saw?"

The boy had not noticed. He had reached the limit of his observations, and no amount of further questioning could elicit anything more from him. This Mr. Gryce soon saw, and giving him into the charge of one of his assistants who was on duty at this place, he proceeded back to the ill-omened house where the tragedy itself had occurred.

"Any one waiting for me?" he inquired of Styles, who came to the door.

"Yes, sir; a young man; name, Hines. Says he's an electrician."

"That's the man I want. Where is he?"

"In the parlor, sir."

"Good! I'll see him. But don't let any one else in. Anybody upstairs?"

"No, sir, all gone. Shall I go up or stay here?"

"You'd better go up. I'll look after the door."

Styles nodded, and went toward the stairs, up which he presently disappeared. Mr. Gryce proceeded to the parlor.

A dapper young man with an intelligent eye rose to meet him. "You sent for me," said he.

The detective nodded, asked a few questions, and seeming satisfied with the replies he received, led the way into Mr. Adams's study, from which the body had been removed to an upper room. As they entered, a mild light greeted them from a candle which, by Mr. Gryce's orders, had been placed on a small side table near the door. But once in, Mr. Gryce approached the larger table in the centre of the room, and placing his hand on one of the buttons before him, asked his companion to be kind enough to blow out the candle. This he did, leaving the room for a moment in total darkness. Then with a sudden burst of illumination, a marvellous glow of a deep violet color shot over the whole room, and the two men turned and faced each other both with inquiry in their looks, so unexpected was this theatrical effect to the one, and so inexplicable its cause and purpose to the other.

"That is but one slide," remarked Mr. Gryce. "Now I will press another button, and the color changes to—pink, as you see. This one produces green, this one white, and this a bilious yellow, which is not becoming to either of us, I am sure. Now will you examine the connection, and see if there is anything peculiar about it?"

Mr. Hines at once set to work. But beyond the fact that the whole contrivance was the work of an amateur hand, he found nothing strange about it, except the fact that it worked so well.

Mr. Gryce showed disappointment.

"He made it, then, himself?" he asked.

"Undoubtedly, or some one else equally unacquainted with the latest method of wiring."

"Will you look at these books over here and see if sufficient knowledge can be got from them to enable an amateur to rig up such an arrangement as this?"

Mr. Hines glanced at the shelf which Mr. Gryce had pointed out, and without taking out the books, answered briefly:

"A man with a deft hand and a scientific turn of mind might, by the aid of these, do all you see here and more. The aptitude is all."

"Then I'm afraid Mr. Adams had the aptitude," was the dry response. There was disappointment in the tone. Why, his next words served to show. "A man with a turn for mechanical contrivances often wastes much time and money on useless toys only fit for children to play with. Look at that bird cage now. Perched at a height totally beyond the reach of any one without a ladder, it must owe its very evident usefulness (for you see it holds a rather lively occupant) to some contrivance by which it can be raised and lowered at will. Where is that contrivance? Can you find it?"

The expert thought he could. And, sure enough, after some ineffectual searching, he came upon another button well hid amid the tapestry on the wall, which, when pressed, caused something to be disengaged which gradually lowered the cage within reach of Mr. Gryce's hand.

"We will not send this poor bird aloft again," said he, detaching the cage and holding it for a moment in his hand. "An English starling is none too common in this country. Hark! he is going to speak."

But the sharp-eyed bird, warned perhaps by the emphatic gesture of the detective that silence would be more in order at this moment than his usual appeal to "remember Evelyn," whisked about in his cage for an instant, and then subsided into a doze, which may have been real, and may have been assumed under the fascinating eye of the old gentleman who held him. Mr. Gryce placed the cage on the floor, and idly, or because the play pleased him, old and staid as he was, pressed another button on the table—a button he had hitherto neglected touching—and glanced around to see what color the light would now assume.

But the yellow glare remained. The investigation which the apparatus had gone through had probably disarranged the wires. With a shrug he was moving off, when he suddenly made a hurried gesture, directing the attention of the expert to a fact for which neither of them was prepared. The opening which led into the antechamber, and which was the sole means of communication with the rest of the house, was slowly closing. From a yard's breadth it became a foot; from a foot it became an inch; from an inch——

"Well, that is certainly the contrivance of a lazy man," laughed the expert. "Seated in his chair here, he can close his door at will. No shouting after a deaf servant, no awkward stumbling over rugs to shut it himself. I don't know but I approve of this contrivance, only——" here he caught a rather serious expression on Mr. Gryce's face—"the slide seems to be of a somewhat curious construction. It is not made of wood, as any sensible door ought to be, but of——"

"Steel," finished Mr. Gryce in an odd tone. "This is the strangest thing yet. It begins to look as if Mr. Adams was daft on electrical contrivances."

"And as if we were prisoners here," supplemented the other. "I do not see any means for drawing this slide back."

"Oh, there's another button for that, of course," Mr. Gryce carelessly remarked.

But they failed to find one.

"If you don't object," observed Mr. Gryce, after five minutes of useless search, "I will turn a more cheerful light upon the scene. Yellow does not seem to fit the occasion."

"Give us rose, for unless you have some one on the other side of this steel plate, we seem likely to remain here till morning."

"There is a man upstairs whom we may perhaps make hear, but what does this contrivance portend? It has a serious look to me, when you consider that every window in these two rooms has been built up almost under the roof."

"Yes; a very strange look. But before engaging in its consideration I should like a breath of fresh air. I cannot do anything while in confinement. My brain won't work."

Meanwhile Mr. Gryce was engaged in examining the huge plate of steel which served as a barrier to their egress. He found that it had been made—certainly at great expense—to fit the curve of the walls through which it passed. This was a discovery of some consequence, causing Mr. Gryce to grow still more thoughtful and to eye the smooth steel plate under his hand with an air of marked distrust.

"Mr. Adams carried his taste for the mechanical to great extremes," he remarked to the slightly uneasy man beside him. "This slide is very carefully fitted, and, if I am not mistaken, it will stand some battering before we are released."

"I wish that his interest in electricity had led him to attach such a simple thing as a bell."

"True, we have come across no bell."

"It would have smacked too much of the ordinary to please him."

"Besides, his only servant was deaf."

"Try the effect of a blow, a quick blow with this silver-mounted alpenstock. Some one should hear and come to our assistance."

"I will try my whistle first; it will be better understood."

But though Mr. Gryce both whistled and struck many a resounding knock upon the barrier before them, it was an hour before he could draw the attention of Styles, and five hours before an opening could be effected in the wall large enough to admit of their escape, so firmly was this barrier of steel fixed across the sole outlet from this remarkable room.