"Curse that green stuff!" said Bullard under his breath. "I'd sooner handle a bunch of live wires."

He was standing in front of the clock, in the glow of an overhanging lamp, the only one he had switched on on entering the firelit room.

The pendulum in its callous swing fairly blazed. There was no sound save a half-stifled, irritating ticking.

Bullard presented rather a curious, if not uncanny, spectacle then. His countenance was covered by a glass mask such as the chemist dons while preparing or studying some highly unstable and dangerous substance. Even more than death he feared pain and disfigurement. His method of dealing with Christopher's clock had been carefully thought out. In the rainproof coat which he wore was a respirator, oxygenated, as well as sundry little tools. For it was the green fluid that had engaged his wits most seriously: it must be got rid of; its powers, whatever they were, dispersed, before he dared tackle the clock itself; and the dispersal must be effected from the greatest distance possible.

Well, he had conceived a way which promised but moderate risk to his own person. Having finished his brief outward examination of the clock, he produced a disk of white paper, an inch and a half in diameter, gummed on one side. Raising the mask slightly, he moistened the disk, and applied it to the clock's case, almost at the bottom of the reservoir. Against the green background the mark showed very distinctly. For a moment or two he regarded it critically, then went to the door and turned the key. He stepped briskly up the room, halting at the heavy brown curtains drawn across the bay-window.

From inside his coat he brought a gleaming weapon with a long barrel and an unusually large butt—an air pistol of great power and reliability. In the old South African times Bullard had been a notable shot with rifle and revolver, and practice during the last few days had shown him that his hand and eye still retained a good deal of their cunning. Moreover, it was an easy mark he had before him now. The chief risk lay in an extremely violent explosion of the green fluid, but he hardly believed in such a result. Christopher was sure to have thought of something more subtle than mere widespread destruction, which might involve friends, not to mention property, no less than enemies. Something that burned, something that asphyxiated—something undoubtedly cruel and treacherous and horrible—existed in that green fluid; but when its time came, it would attack its victim with little sound, if not in absolute silence. So Bullard had imagined it, though he was prepared to find himself wrong.

The pistol was already loaded, its charge of compressed air awaiting but the touch of release. Bullard undid the safety-catch, took a glance round, and passed between the curtains, re-drawing them till they almost touched. With his left hand he grasped the edges at a level with his chin, leaving a narrow aperture above that level through which he could aim. If an explosion did take place, he was fairly secure from flying fragments; if the atmosphere became too perilous, the window was at hand.

He raised the weapon to the aperture and protruded the barrel. An easy shot, indeed! He would soon know what … Damn! what was that? Footsteps on the gravel beneath the window? Withdrawing the pistol, he moved to the window and listened. The fastenings of the mask encumbered his hearing; he could not be sure. But, next moment, peering through the misty pane on the right he saw a man's figure, too small for either Craig or France, move from the steps into the ruddily lighted doorway. And far away, as it seemed, an electric bell purred.

Wrath at the interruption rather than fear of discovery and capture possessed Bullard. Caw was helpless for the present, and it was not the old housekeeper's business to answer the bell. The visitor would have to wait awhile. Anyway, there was plenty of time for escape…. But was he going to flee empty-handed, leaving that cursed clock unexplored?

He turned quickly back to the curtains, and again protruded the pistol—and all but dropped it.

Between him and the clock a girl was standing—a girl in an apple-green evening frock. She had nut-brown hair and a beautiful neck, and she was inclined to plumpness. Apparently she was watching the pendulum. Soon, however, she moved and looked around her. There was a slight flush on the delicate tan of her cheeks, and she smiled faintly as at some foolish thought. Then, glancing at something in her hand, she shook her head while a tiny frown superseded the smile.

She stepped to the door and turned the handle—and gave a little gasp. Bullard saw her colour go out, saw her shoulder seek the support of the door. In that instant he might have over-awed her, stunned her with alarm, but in the next she straightened up and did an unexpected thing. She drew the key from the locked door and walked deliberately to the writing table. For a moment she seemed to require the support of its ledge, yet steadily enough she passed back to the clock.

There she wheeled about. Up went her right hand holding a little revolver. She spoke softly, not unwaveringly, but quite clearly.

"Whoever you are, I think you had better come out. They will be here immediately. I've rung for them. You can't escape!"

There was no response. Bullard was thinking hard. Ought he to overpower her or risk the long drop from the window?

"I will count three," she said, "and if you don't come out, I will shoot!
One … two … th—"

"Do not forget," said a muffled voice, "that I can shoot also."

"You horrid pig!" she cried. "Take that!" Crack went the revolver—crash went the bulb and shade above the writing-table.

Bullard stepped forth. There was a greyish shade on his face, but his lips smiled stiffly behind the glass mask.

"Stand away from the clock, and be good enough to return the key to the door," he said.

The sight of him daunted her, yet not for long. She fired again—blindly, one may suppose. The bullet passed over his head, between the curtains, and through the window. A sound of vigorous knocking came from below.

"You little devil!" snarled Bullard, and ran at her.

Then her nerve weakened and she darted toward the door of the passage. Ere she could reach it, it flew open, and, dropping the revolver, she fell into the arms of the panting Alan.

"Good God! what's this?" he cried at the extraordinary appearance of Bullard and the smoke wreaths in the atmosphere. "Are you all right?" he whispered to the girl.

Teddy dashed in, gave a shout and made for Bullard, only to be brought up short by a shining muzzle almost in his face.

From downstairs a female voice rose in shrieks; from the stairs came a man's, shouting in a foreign tongue. Next moment there fell a frantic beating on the door.

Marjorie darted from her refuge, thrust home the key and turned it.
Monsieur Guidet almost fell in, crying—

"Quick! Look after Mr. Caw! He was hurt—on the stair!"

As he spoke, Lancaster, Doris, Mr. Harvie and the doctor appeared from the passage.

"Doctor, will you go to Caw?" said Alan rapidly. "He's hurt—downstairs."

Handyside ran out, and Guidet banged the door after him. "Guard it!" he shouted to Teddy. "Let not the pig-hog escape!"

The little Frenchman was beside himself. "So I suspect you right!" he almost screamed. "You think I was greater fool than you look when you ask me to make clock the same for five hundred pounds! Bah! What idiot you was! For I think a little after you go, and I take not many chances. How to get here most quick, I ask myself. The train to Greenock, the ferry to cross the water, and the legs to run three miles. I do so! I arrive!—behold, I arrive in time!" He laughed wildly. "And so you would try to kill him—my clock!" he yelled, and with that, like a furious bantam, ignoring the pistol, he flew at Bullard, tore away the mask and tossed it against the wall.

"Monsieur Guidet!" cried Alan, running forward and catching his arm.
"Leave him to us."

Guidet shook off the clasp. "Pig-hog," he went on, "behold, I pull your nose! There! Also, I flap your face! One! two! I do not waste a good clean card on you, but I will give you satisfaction when you like—after you come out of the jail!"

Alan had grabbed Bullard's right wrist. "Teddy, take the madman away," he cried, and Teddy removed Guidet, who went obediently, but blowing like a porpoise, to a seat by the wall.

Lancaster, looking ill, had sunk into an easy-chair by the fire. His
daughter, pale but composed, stood beside him, her hand on his shoulder.
She still feared Bullard: even now she was ready for sacrifice. Mr.
Harvie, lost in amazement, had not got beyond the threshold.

As for Bullard, he had gone white to the lips at the Frenchman's affront; his expression was diabolical. Wrenching his wrist from Alan's grasp, he stepped back until he stood framed in the curtains. His black eyes stared straight in front of him, at the clock, perhaps; perhaps into the future.

Alan went back to the door, and whispered to Marjorie: "Go beside Doris, please." Then he turned to Bullard.

"I may as well tell you," he said, "that unless my servant Caw is another of your victims, like Flitch, we shall neither attempt to injure you nor give you in charge; the reason for that is our affair."

At this Teddy found it necessary to restrain Monsieur Guidet.

"But, on the other hand," Alan continued, "you are not going to walk out of this house as easily as you seem to have entered. In fact, you are not going to leave this house until many things have been settled."

Bullard gave him a glance. "Indeed!" he said quietly. "And what does Mr.
Lancaster say to that?"

"Mr. Lancaster is not going to be troubled over this matter," Alan replied calmly, "and you will have no opportunities for troubling him on any other matter. We happen to have a nice, dry cellar, and—well, in short, you are our prisoner, Mr. Bullard—"

Mr. Harvie took a step forward. This was too much for his legal mind. "My dear Mr. Craig," he began, "pray consider carefully—"

"Oh, please, for goodness' sake, keep quiet, Mr. Harvie," Marjorie impulsively interposed, and he collapsed, partly, it may have been, from astonishment.

"For how long, may I ask," sneered Bullard, "am I to have the felicity of your hospitality?"

"Till the clock stops."

A short silence was broken by Monsieur Guidet's clapping his hands and exclaiming: "How you like that, pig-hog? Bravo, Mr. Craik! That was a good bean to give him!"

Marjorie and Teddy laughed, and the others, excepting Lancaster, smiled. And just then the doctor entered supporting Caw, who looked dazed and wretched. Alan shook his limp hand and helped him to a seat beside Guidet—which was an error of judgment, for the Frenchman's eloquence was loosened afresh.

"Ah, poor Mr. Caw," he cried, patting the sufferer affectionately. "But never mind, for now you have the enemy on the toast! Cheer up, for I will tell you a good choke! Figure it to yourself, the pig-hog comes here with a glass dish over his bad face—he was so fearful of my clock that it would hurt him—he had so great terror of the green fluid—ha! ha!—I must laugh, it was so very droll." Then he flashed round on Bullard. "But listen, pig-hog, and I tell you the secret of the dreadful, fearful, terrible, awful green fluid! I know the secret, for I make it myself. It is a kind of fish—what you call a cod—understand? And I make it with the oil of castor and some nice colourings! VoilÀ! I could laugh for weeks and fortnights, and—"

"Look out!" shouted Teddy, and sprang forward—too late.

"Till the clock stops," said Bullard in a thick voice, and fired at it.
Then he flung the pistol behind him and grinned.

Teddy secured Guidet just in time, and a silence fell that seemed to last for minutes.

The bullet, having made a starry hole in the glass, had pierced the face an inch below its centre, and as the company stared, the pendulum shuddered and fell with a little plash into the green liquid.

A wild cry came from the Frenchman—"Miracle!"—and he fell to hugging poor Caw.

As though the others had ceased to exist, Bullard strode forward. Now his countenance was congested, his eyes glazed. "The diamonds!" he muttered. "Where are the—"

He stopped short, as did Alan and Teddy, who had started to intercept him,—stopped short, as did every other human movement in that room at the sound of a voice—a voice emanating from no person present.

Far and faint it sounded, but distinct enough for the hearing of all.

"Do not be alarmed," it said, and paused.

And Bullard was ghastly again, and Lancaster gasped and shivered and put his hands to his face. Marjorie caught Doris's hand, and Caw tried to rise. The others stared at the clock.

The voice slowly proceeded—

"These are my instructions to my nephew, Alan Craig, respecting the diamonds once mine, now his; and if Alan has not returned, to my servant Caw, and failing him, to my lawyer, Mr. George Harvie, who shall then open the letter marked 'last resort,' which I leave in his care. But I make this record in the full belief that my nephew lives and will hear my words." A pause.

Bullard threw himself on the couch. "'His master's voice, Caw,'" he sneered most bitterly.

No one answered save the impulsive Marjorie.

"Cad!" she said clearly.

The voice resumed:

"Alan, you will have the diamonds divided expertly and without delay into three portions of equal value, and you will hand one portion to Miss Marjorie Handyside, the second to Miss Doris Lancaster, yourself retaining the third. I make no restrictions of any sort. I also desire you to present the pendulum intact to Monsieur Guidet, the maker of the clock, provided he has proved faithful. Finally, I ask you to present to my one-time friend, Francis Bullard, the Green Box left in the deep drawer of my writing-table, unless he has already obtained possession of the same, along with the key which Mr. Harvie will provide. And may God bless and deal gently with us all!—even with the traitor in our midst. Farewell."

There was another silence. Doris was kneeling, her arms round her father, as though to protect him, and Bullard had risen; the others had scarcely changed their positions.

Mr. Harvie cleared his throat. "Really, my dear Mr. Craig," he said, "all this is most interesting, but, I beg leave to say, extremely irregular. And—and where are the—"

"I almost forgot to say," replied the voice—and you might have fancied a repressed chuckle—"that the diamonds are deposited, in my nephew's name, with the Bank of Scotland, Glasgow. Once more, farewell."

And with that the clock, having performed its duty, though so long before its time, disintegrated, the works falling piecemeal into the green fluid, there forming a melancholy little heap of submerged wreckage.

No one seemed to know what to say, until Mr. Harvie came to the rescue.
He advanced and congratulated Marjorie.

"And you, too, Miss Lancaster," he said kindly.

Doris rose and gave him her hand. "It's really true, isn't it?" she whispered. "And I can do anything I like with them?"

"Anything you like, my dear."

Alan and Teddy approached the girls, but Bullard was before them. The man refused to believe he was beaten.

"Doris," he said, almost pleasantly, "now that the clock has stopped, I feel at liberty to announce our engagement."

She looked at him bravely, but did not speak.

He lowered his voice. "Your father's debt to the Syndicate is paid, but—"

"Oh, you worm!" cried Marjorie. "Where's my revolver?"

But Alan took him by the collar and slung him halfway across the room, crying savagely: "How dare you speak to a lady?"

"Bravo, Mr. Craik!" Guidet chuckled. "Another good bean!"

"Leave him to me," said Teddy. "He has asked for it, and, by Heaven, he's going to get it! Look here, Bullard!" He held up an inch of fine gold chain with a nugget attached, and Bullard wilted. "If you aren't out of this country within three days, and if you ever defile it again, I'll use this, though I should get five years for holding it back. Now go!"

Bullard turned to the door.

"Oh, stop him!" feebly cried Caw. "He must not go without the Green Box."

Bullard made a dash, but the Frenchman was before him and held the door till Teddy brought box and key. For an instant Bullard looked as if he would send the thing crashing amongst the midst of them all. Then he took it and went.

"Mr. France," said Caw, "please take my revolver and see that he carries the box right off the premises."

"I'll see him to the gates," said Teddy.

* * * * *

And so Francis Bullard realised that he was beaten at last. Yet even in the agony of rage and hate and defeat that shook his being as he turned from the gates of Grey House, he ignored despair. Nothing was final! South Africa was before him! There was money to be made! There was revenge to be planned…. Revenge! He could think of nothing else—not even of some one who might be crazy for revenge on himself.

He came to the wood, started the car, and backed it out to the road. Then he set off for Glasgow at a more reckless pace than usual—and suddenly remembered that the Green Box was on the seat beside him. Fool that he was!—the thing must be got rid of! The water—that was the place. He prepared to slow down. No, not yet. Better get past that bit where the road ran so high above the shore. He put on speed again, and then—

A snarl behind him, a hot breath on his ear, and two hands fastened viciously about his neck.

"Stop the car!" quacked the voice of Edwin Marvel. "My turn now! I've been waiting for this, you beast, you liar, you swindler! Stop the car!" repeated the madman, and wrenched at his captive's throat so that the latter's hands were torn from the wheel.

Bullard's prayer, warning, or whatever it was, came forth in a mere gurgle. The car swerved, left the road, ran up a short, gentle, grassy slope, tilted at the summit, toppled and plunged to the rocky shore.

There was an appalling explosion.