THE HIDDEN TRAP

PROFESSOR ROGER BISCAYNE was reading the list of names from the sheet of paper that had been discovered.

All were listening, including Cardona, although the detective appeared to be otherwise engaged.

Wedged between the sections of the radiator, he was examining the space that had been hewn in the wall.

“Here are the names,” declared Biscayne. “Louis Glenn. Thomas Sutton. James Throckmorton. Arthur Wilhelm.

“Listen to this statement, written beneath:

“I, Silas Harshaw, sound of mind, do declare and proclaim these men as my enemies.

“Louis Glenn urged me to spend my little pittance in stock that proved worthless. Thomas Sutton refused to listen to me, when I told him of my great invention.

“James Throckmorton questioned me suspiciously, and demanded that I tell him all my plans. Arthur Wilhelm furnished me with funds, but did so grudgingly, expecting much from little.

“I believe that any one of these men would steal my brains if they could do so.

“Hence if any one of them should fall into the snare that I have laid, his death will be on his own head.

“Let them beware! Alive or dead, I can thwart their plans of theft!”

“The man was crazy!” exclaimed Wilhelm. “I would have given him all the money he wanted, if he had shown some results. But I wasn’t going to throw my cash away.

“To think of it! He tried to kill me!” Joe Cardona was calling from the spot beside the window.

Biscayne placed the paper in the hands of the commissioner, and hurried to the other end of the room. The others followed.

Peering into the open space, they saw the muzzle of a revolver. The weapon had been mounted at the back of the space, set between braces.

It was connected to the sliding panel by a neatly fashioned contrivance that was to set to press the trigger of the gun every time the slide came up.

Cardona removed the gun and brought it out. As he stepped away, he released pressure on the sides of the radiator, and they swung back to their original position.

A sharp click told that the sections had automatically locked.

“Five chambers,” remarked Cardona. “Wonder where the old guy dug up this rod. A .32. Hm-m-m. Four cartridges used.

“One for Harshaw. One for Max Parker. One just now. Wonder when the other was fired.”

“That hardly matters,” said Biscayne. “Let’s look in that compartment again.”

He pulled the knob of the radiator. This time, Cardona opened the metal sections with impunity, for the menace had been removed.

He discovered a small stack of letters and some papers. Also another object, which Cardona seized with a sharp exclamation.

It was a cigarette box, bearing the name, “Istanbul.”

“The brand that Glenn smoked!” proclaimed Cardona.

Biscayne was looking at the envelopes. There were only three.

One was addressed to Louis Glenn; the second to James Throckmorton; the third to Arthur Wilhelm. They were written in a scrawl — a scrawl which Cardona recognized as the writing on the envelope which had been found by Thomas Sutton’s wastebasket.

That envelope had borne the instructions to seek the gold-headed cane in the fatal closet beneath the stairs.

The envelopes were not sealed. Biscayne read the letter addressed to Louis Glenn. It was full of vague remarks Biscayne quoted in part:

“We have not met for years… You have forgotten me… You made me lose my money, but I shall be wealthy, now! My brain will bring me millions…”

Laying the letter aside, Biscayne took the one addressed to James Throckmorton. He read these statements:

“You wanted to know about my inventions… They are completed now… The one will bring me millions. You will know all about it then…”

The letter to Wilhelm carried a different tone as Biscayne read it:

“My task is done… My model lies complete, where it is safe… It is at my home…”

“Here’s another letter,” remarked Cardona, going through the odd papers which he had found. “It’s to Thomas Sutton, but it has no envelope. Listen. “It says that Sutton had no faith; that he will hear great things from the man whom he had ignored.”

Biscayne nodded as he received the letter and quoted aloud:

“My visits to you were in vain. You failed me. All have been against me… I have prevailed… You missed your greatest opportunity…”

Cardona was pondering. He smacked his fist against his other palm and looked up at his companions.

“These letters were going to be mailed,” he declared. “The old man must have changed his mind. He sent Thomas Sutton a typed letter, but used the envelope that he had prepared for this one.

“All those death notes must have come from Harshaw — even the one about himself! But who sent them?”

“Harshaw sent them,” declared Biscayne suddenly. “Sent them from this apartment. He must have intended to send these letters, too — probably while he was away.

“When did you advise him to take a trip, Doctor Fredericks?”

“Often,” said the physician. “He never wanted to go. He said he was afraid to leave. When I urged him, he said that he would make plans so he could go.

“When I finally told him he must go away, he agreed to leave at once—”

“That’s it!” exclaimed Biscayne. “He had these letters ready. He wanted them to be delivered while he was away, so that his enemies would think he was at home.

“Then, with death staring at him, he turned to another scheme more insidious than idle threats or inferences.

“He arranged the killings — and sent the death notes!”

“But how?” came Cardona’s question.

“One came from this floor tonight,” said Biscayne thoughtfully. “There was no one here to mail it.

“Look at the side wall of this room. The mail chute must be on the other side—”

Cardona was tapping at the wall. Eagerly he searched, and the others joined with him. Keen though these men were, the secret mocked them.

“We’ll smash that mail chute!” exclaimed Cardona grimly. “Wait until I get Mayhew. We’ll find it from the other side—”

“Here!” The cry came from Biscayne. He was rapping at the baseboard of the wall. “This may be it!”

Cardona was with the professor. Together, they pried effectively. The small portion of flooring yielded. The baseboard came open.

The little cache was disclosed. The clockwork was still ticking, but now there was no letter projecting from the clips.

Fumbling with the mechanical box, Cardona pried off the lid.

The interior of the box showed a set of thin sections, more than twelve in number, each slightly larger than an envelope.

“One every forty-eight hours,” said the detective to Biscayne. “That’s how it was set—”

“No,” said Biscayne, “it must have been gauged for twenty-four. That’s why the Sutton letter came in between the death notes.

“By leaving empty spaces, the deliveries could be interrupted on days they were not needed.”

“Right,” declared Cardona.

Biscayne began to pace up and down the room. His mind was at work.

“If I had known Harshaw well,” said the professor, “I might have divined some of this beforehand.

“Three men have died because of his fiendish plotting. We can be thankful only that the fourth was saved — my cousin, Arthur Wilhelm.

“Silas Harshaw was unquestionably eccentric,” Biscayne continued. “He imagined enmities, and saw schemes where there were none.

“He wanted to protect that hiding place behind the radiator — that is evident. So he not only made it difficult to find. He placed the apparatus there, to thwart any man who might come.”

“What about Max Parker?” queried Cardona.

“A cross-purpose,” responded Biscayne. “There might be a connection between Max Parker and Homer Briggs. It seems evident that Parker must have blundered in upon the trap that was laid for others.”

“IF he was an enemy, the old man would have mentioned it,” commented Cardona. “How do you figure that Harshaw worked the big killings? He must have bumped himself off to start.”

“Undoubtedly,” declared Biscayne. “Knowing that he had not long to live, he used his own trap for suicide. But he must have wanted the others to die, too.

“Take Glenn, for instance. The old man was a chemist. Those cigarettes which—”

“I was right,” interrupted Cardona. “Harshaw must have got a couple of packs — we found one in the strong box, here. Then he must have planted it in Glenn’s Tuxedo; that box that Glenn had with him.

“One poisoned cigarette in the box! That’s what did it. I had it right. But how did Harshaw put it there the box — in the Tuxedo—”

“That we may never learn,” replied Biscayne. “We have the motive. We have evidence. That is sufficient for the present.

“Let us consider Thomas Sutton. The old man went to his house, according to the letter. He must have heard Sutton speak about the cane.

“He must have noticed that closet door. He was a shrewd man, was Silas Harshaw.”

“We’ve linked him there,” agreed Cardona. “We’ve already tied him up with Throckmorton. Do you think he fixed the hose on the gas lamp?”

“In all probability,” said Biscayne. “Of course, a man was discovered in Throckmorton’s home. There are details that are still bewildering.

“The attempt upon my cousin Arthur’s life tonight, however, settles the case against Silas Harshaw.

“That bomb is crudely fashioned. Perhaps it was made in the old man’s workshop, right here.”

“We’ll look!” cried Cardona.

“Not yet,” said Biscayne. “We have work to do first. Perhaps there is more to find.”

“The old man’s model?”

“Yes.”

Cardona looked around the room. He spied the closed radiator. He turned quickly to Biscayne.

“That shooter behind the radiator!” he exclaimed. “It wasn’t there just to keep people from finding a few papers and envelopes. That’s where the model is, I’ll bet!”

Eagerly, the detective pulled the knob of the radiator and opened the sections.

He realized again the efficiency of this trap. A man shot here would topple backward — falling, he would lose hold, and the radiator would close!

It had happened with Silas Harshaw. It had happened with Max Parker. But it could not happen now, since the clamped revolver had been removed.

Peering in the light of his torch, Cardona spied the flat bottom of the shallow hole inside the wall.

His fingers pried, and were rewarded. The bottom of the strong box swung upward. The glow of the flashlight spotted a square wooden box.

Dropping his light, Cardona drew the box out and set it in the middle of the floor. He lifted the lid.

Inside was a metal device, more than one foot square. It seemed strangely light as Cardona removed it from the box.

It had dials and knobs, with little posts for the attachment of wires.

It was the model of the remote-control machine — the invention of which had been the life work of Silas Harshaw!