“A selenium cell,” he explained.  “Only when light falls on it does it become a good conductor of electricity.  Then the bell will ring.”

Just before making the connection he placed his hat over the cell.  Then he lifted the hat.  The light fell on it and the bell rang.  He replaced the hat and the bell stopped.  It was evidently a very peculiar property of the substance, selenium.

Just then there came a knock at the door.  I opened it.

“Hello, Chase,” greeted Kennedy.  “Well, I’ve found the new headquarters all right,—­over on the west side.”

Kennedy picked up the selenium cell and a long coil of fine wire which he placed in a bag.  Then he took another bag already packed and, shifting them between us, we hurried down town.

Near the vacant lot, back of the new headquarters, was an old broken down house.  Through the rear of it we entered.

I started back in astonishment as we found eight or ten policemen already there.  Kennedy had ordered them to be ready for a raid and they had dropped in one at a time without attracting attention.

“Well, men,” he greeted them, “I see you found the place all right.  Now, in a little while Jameson will return with two wires.  Attach them to the bell which I will leave here.  When it rings, raid the house.  Jameson will lead you to it.  Come, Walter,” he added, picking up the bags.

Ten minutes later, outside the new headquarters, a crouched up figure, carrying a small package, his face hidden under his soft hat and up-turned collar, could have been seen slinking along until he came to the steps.

He went up and peered through the aperture of the doorway.  Then he rang the bell.  Twice he raised his hand and clenched it in the now familiar clutch.

A crook inside saw it through the aperture and opened the door.  The figure entered and almost before the door was shut tied the masking handkerchief over his face, which hid his identity from even the most trusted lieutenants.  The crook bowed to the chief, who, with a growl as though of recognition, moved down the hall.

As he came to the room from which Spike had been sent on his mission, the same group was seated in the thick tobacco smoke.

“You fellows clear out,” he growled.  “I want to be alone.”

“The old man is peeved,” muttered one, outside, as they left.

The weird figure gazed about the room to be sure that he was alone.

When Craig and I left the police he had given me most minute instructions which I was now following out to the letter.

“I want you to hide there,” he said, indicating a barrel back of the house next to the hang-out.  “When you see a wire come down from the headquarters, take it and carry it across the lot to the old house.  Attach it to the bell; then wait.  When it rings, raid the Clutching Hand joint.”

I waited what seemed to be an interminable time back of the barrel and it is no joke hiding back of a barrel.