RUBBING ELBOWS WITH DEATH.

Matt had neither the time nor the strength to manifest any surprise over the startling revelation made by Glennie. Not only that, but his brain was in such a condition it was well-nigh incapable of surprise.

In that critical moment when he felt a terrifying helplessness surely but steadily creeping over him, he centred every effort on the attempt to make Ah Sin a prisoner.

Swiftly as a lightning flash the idea struck through Matt's brain that the Chinaman had all to do with the baffling situation aboard the Grampus. If Matt could drag him down and secure him he felt that, at a later moment, the treacherous Celestial might be dealt with as his evil deeds justified.

But the work the king of the motor boys had mapped out for himself exceeded his powers. There was none to come to his aid. Below, in the tank room and motor room, was a silence undisturbed by human voice or movement, and there, in the periscope chamber, the only noise to be heard was the deep breathing of Matt's unconscious friends and the rattling sounds of the scuffle going forward between the young motorist and Ah Sin.

The slouch hat and the false queue were kicked into one corner. Ah Sin's long, lean fingers were gripping Matt's throat. There was no look of hate, or anger, or even of determination in the Chinaman's face; the expression was blank and saturnine, as though he was merely a tool, operated by wires like a puppet and carrying out the will of some one in high authority.

Suddenly, putting forth all his strength, Ah Sin lifted Matt by the throat and threw him bodily across Speake and against the edge of the locker. Matt tried to rise, but found it impossible.

The awful weakness held him in thrall and was fastening gyves upon his wrists. Soon he would be utterly helpless, like those lying around him, and what would Ah Sin then do to the Grampus?

A spasm of alarm and apprehension rushed through the young motorist. Was this to be the end of the submarine's voyage? Was the sale of the boat to the government destined never to be consummated?

Vaguely Matt thought of Captain Nemo, Jr., lying sick in that house in Belize, of his unswerving confidence in the king of the motor boys, and of his tremendous disappointment if anything happened to the submarine during her daring cruise.

All this brought every ounce of Matt's failing strength back to him. He shoved his hand along the side of the locker and twined his fingers about the grip of the revolver dropped by Glennie, then, with a despairing effort, he lifted himself on one elbow and again directed his gaze at the Chinaman.

Ah Sin had not been idle. He was holding something in his hand—a round object from which hung a long, black string. The Chinaman was lighting a match and touching the flame to the end of the string.

Matt could not see very distinctly, for everything in the periscope chamber, even the chamber itself, was reeling about him in fantastic lines.

The glow at the end of the black string sputtered and hissed. Stepping over to one corner, Ah Sin placed the round object on the floor with exceeding care, pulling out the string so that it lay in a straight line, the burning end pointed toward the centre of the room.

For a moment Ah Sin knelt and stared. His face was still inscrutable, his eyes showing nothing more than a mild interest in his fiendish work.

A bomb!

The realization broke over Matt's benumbed brain like a thunder-clap.

Ah Sin was seeking to blow up the submarine, annihilating not only the boat, but those aboard as well.

On Matt alone depended the salvation of the Grampus and her crew. And he was almost helpless in the grip of the baneful spell that had fallen over every one on board, with the exception of the Chinaman!

Matt lifted the revolver unsteadily. A report rang out, sending wild echoes clattering through the steel hull.

The bullet missed the kneeling Chinaman, struck clanging against the curved iron plates, glanced against the bulkhead above the locker, and dropped flattened and harmless at the side of Glennie.

Owing to Matt's unsteady hand the Chinaman had escaped the bit of lead, but he was startled and frightened. Leaping up he whirled and peered at Matt. The latter still clutched the revolver, but his hand swayed back and forth as he leveled it.

Ah Sin made a quick jump toward Matt, evidently with the intention of disarming him; but there was something in the lad's wide, straining eyes that caused him to change his mind. Swerving aside he rushed at the ladder, mounted swiftly, and disappeared through the hatch.

With a fierce effort Matt concentrated his wandering wits upon the bomb. Someway, somehow, he must reach the infernal machine and extinguish the fuse.

Dropping the revolver, he rolled over and over, a lurch of the boat, running erratically with no guiding hand at either wheel or motor, helping him to reach the foot of the periscope table.

With the utmost difficulty he caught the legs of the rigidly secured table and pulled himself to his knees. The cup, from which he had taken only a few swallows of coffee, stood on the floor just below the end of the table, and not more than a foot from the burning fuse. By a miracle the cup had not been overturned.

For him to reach the fuse in his weakened condition was impossible; but, if he could regain his feet and kick the cup over the coffee that remained in it might quench the fire of the fuse.

Three times he endeavored to draw himself erect by means of the table, but succeeded only in dropping backward as though pushed by a heavy, resistless hand. But the fourth time he managed to remain upright, trembling with the strain he had put upon himself.

It seemed a trifling thing to overset the coffee-cup, but Motor Matt had never planned a harder task.

There are but few things in this life, however, that will not yield to pluck and determination, and fortune favored Matt in his grave fight.

The Grampus pitched forward, rising aft and making a steep incline of the floor. Matt's feet slipped, and he lost his hold on the table. As he came heavily down he shot against a stool, which was overturned and upset the cup. The liquid in the cup had slopped over the sides, and with the overturning a miniature wave of brown rolled along the inclined floor.

There followed a hiss as it engulfed the tiny blaze at the end of the fuse, and then a little spiral of smoke eddied upward.

This much Matt saw, and a fierce exultation ran through him. The bomb was harmless—but where was Ah Sin? Would he not come back, discover what Matt had accomplished, and again set a match to the fuse?

This might happen, but there was nothing Motor Matt could do to prevent it.

He had taken only a few swallows of the coffee, and to this, and to his superior powers of endurance, was due the fact that he had kept his senses and a remnant of his strength long enough to accomplish what he had.

But now a wave of darkness rolled over him. As unconscious of what was taking place around him as he was helpless to prevent further disaster, his head fell back and he lay as one dead among his silent and motionless companions.