Bowing low again, the secretary shuffled across and down again through the hatchway, closing the door as he descended.

Long Sin read the note once more, while his inscrutable face assumed an expression of malicious cunning.  Then he glanced at his heavy gold watch.

With an air of deliberation, he reached for a match and struck it.  He had just placed the paper in the flame when suddenly he seemed to change his mind.  He hastily blew out the match which had destroyed only a corner of the paper, then folded the note carefully and placed it in his pocket.

A few moments later, with a malignant chuckle, Long Sin rose slowly and left the room.

. . . . . . . .

Meanwhile, the master criminal was busily engaged in putting the finishing touches to a final scheme of fiendish ingenuity for the absolute destruction of Craig Kennedy.

He had been at work in a small room, fitted up as a sort of laboratory, in the mysterious house which now served as his headquarters.

On all sides were shelves filled with bottles of deadly liquids and scientific apparatus for crime.  Jars of picric acid, nitric acid, carboys of other chemicals, packages labelled gunpowder, gun cotton and nitroglycerine, as well as carefully stoppered bottles of prussic acid, and the cyanides, arsenic and other poisons made the place bear the look of a veritable devil’s workshop.

Clutching Hand, at a bench in one corner, had just completed an infernal machine of diabolical cunning, and was wrapping it carefully in paper to make an innocent package.

He was interrupted by a knock at the door.  Laying down the bomb he went to answer the summons with a stealthy movement.  There stood Long Sin, who had disguised himself as a Chinese laundryman.

“On time—­good!” growled Clutching Hand surlily as he closed the door with equal care.

No time was wasted in useless formalities.

“This is a bomb,” he went on, pointing to the package.  “Carry it carefully.  On no account let it slip, or you are a dead man.  It must be in Kennedy’s laboratory before night.  Understand?  Can you arrange it?”

Long Sin looked the dangerous package over, then with an impassive look, replied, “Have no fear.  I can do it.  It will be in the laboratory within an hour.  Trust me.”

Long Sin nodded sagely, while Clutching Hand growled his approval as he opened the door and let out the Chinaman.  Long Sin departed as stealthily as he had come, the frightful engine of destruction hugged up carefully under his wide-sleeved coolie shirt.

For a moment Clutching Hand gave himself up to the exquisite contemplation of what he had just done, then turned to clean up his workshop.

. . . . . . . .

In Kennedy’s laboratory I was watching Craig make some experiments with a new X-ray apparatus which had just arrived, occasionally looking through the fluoroscope when he was examining some unusually interesting object.