Suddenly he raised it and hurled the deadly thing down through the hole.

We could hear the imprecations of the crooks as it struck the cellar floor, near them. They had evidently been still cramming jewelry into the capacious maw of the bag. One of them, discovering the bomb, must have advanced toward it, then retreated when he saw how imminent was the explosion.

"Leave the store--quick!" rang out Kennedy's voice.

We backed away as fast as those behind us would permit. Kennedy and Bennett were the last to leave, in fact paused at the door.

Down below the crooks were beating a hasty retreat through a secret entrance which they had effected.

"The bag! The bag!" we could hear one of them bellow.

"The bomb--run!" cried another voice gruffly.

A second later came an ominous silence. The last of the three must have fled.

The explosion that followed lifted us fairly off our feet. A great puff of smoke came belching up through the hole, followed by the crashing of hundreds of dollars' worth of gla.s.s ware in the jewelry shop as fragments of stone, brick and mortar and huge splinters of wood were flung with tremendous force in every direction from the miniature volcano.

As the smoke from the explosion cleared away, Kennedy could be seen, the first to run forward.

Meanwhile Martin's detectives had rushed down a flight of back stairs that led into a coal cellar. With coal shovels and bars, anything they could lay hands on, they attacked the door that opened forward from the coal cellar into the front bas.e.m.e.nt where the robbers had been.

A moment Kennedy and Bennett paused on the brink of the abyss which the bomb had made, waiting for the smoke to decrease. Then they began to climb down cautiously over the piled up wreckage.

The explosion had set the bas.e.m.e.nt afire, but the fire had not gained much headway, by the time they reached the bas.e.m.e.nt. Quickly Kennedy ran to the door into the coal cellar and opened it.

From the other side, Martin, followed by the police and the detectives, burst in.

"Fire!" cried one of the policemen, leaping back to turn in an alarm from the special apparatus upstairs.

All except Martin began beating out the flames, using such weapons as they already held in their hands to batter down the door.

To Martin there was one thing paramount--the jewels.

In the midst of the confusion, Elaine, closely followed by her friend Susie, made her way fearlessly into the stifle of smoke down the stairs.

"There are your jewels, Mr. Martin," cried Kennedy, kicking the precious burlap bag with his foot as if it had been so much ordinary merchandise, and turning toward what was in his mind the most important thing at stake--the direction taken by the agents of the Clutching Hand.

"Thank heaven!" e.j.a.c.u.l.a.t.ed Martin, fairly pouncing on the bag and tearing it open. "They didn't get away with them--after all!" he exclaimed, examining the contents with satisfaction. "See--you must have frightened them off at just the right moment when you sent the bomb back at them."

Elaine and Susie pressed forward eagerly as he poured forth the sparkling stream of gems, intact.

"Wasn't he just simply wonderful!" I heard Susie whisper to Elaine.

Elaine did not answer. She had eyes or ears for nothing now in the melee but Kennedy.

Events were moving rapidly.

The limousine had been standing innocently enough at the curb near the corner, with the taxicab close behind it.

Less than ten minutes after they had entered, three well-dressed men came out of the vacant shop, apparently from the tailor's above, and climbed leisurely into their car.

As the last one entered, he half turned to the taxicab driver, hiding from pa.s.sers-by the sign of the Clutching Hand which the taxicab driver returned, in the same manner. Then the big car whirled up the avenue.

All this we learned later from a street sweeper who was at work nearby.

Down below, while the police and detectives were putting out the fire, Kennedy was examining the wall of the cellar, looking for the spot where the crooks had escaped.

"A secret door!" he exclaimed, as he paused after tapping along the wall to determine its character. "You can see how the force of the explosion has loosened it."

Sure enough, when he pointed it out to us, it was plainly visible. One of the detectives picked up a crowbar and others, still with the hastily selected implements they had seized to fight the fire, started in to pry it open.

As it yielded, Kennedy pushed his way through. Elaine, always utterly fearless, followed. Then the rest of us went through.

There seemed to be nothing, however, that would help us in the cellar next door, and Kennedy mounted the steps of a stairway in the rear.

The stairway led to a sort of storeroom, full of barrels and boxes, but otherwise characterless. When I arrived Kennedy was gingerly holding up the dusters which the crooks had worn.

"We're on the right trail," commented Elaine as he showed them to her, "but where do you suppose the owners are?"

Craig shrugged his shoulders and gave a quick look about. "Evidently they came in from and went away by the street," he observed, hurrying to the door, followed by Elaine.

On the sidewalk, he gazed up the avenue, then catching sight of the street cleaner, called to him.

"Yes, sir," replied the man, stolidly looking up from his work. "I see three gentlemen come out and get into an automobile."

"Which way did they go?" asked Kennedy.

For answer the man jerked his thumb over his shoulder in the general direction uptown.

"Did you notice the number of the car?" asked Craig eagerly.

The man shrugged his shoulders blankly.

With keen glance, Kennedy strained his eyes. Far up the avenue, he could descry the car threading its way in and out among the others, just about disappearing.

A moment later Craig caught sight of the vacant taxicab and crooked his finger at the driver, who answered promptly by cranking his engine.

"You saw that limousine standing there?" asked Craig.

"Yes," nodded the chauffeur with a show of alertness.

"Well, follow it," ordered Kennedy, jumping into the cab.

"Yes, sir."

Craig was just about to close the door when a slight figure flashed past us and a dainty foot was placed on the step.