TWO men approached and Seized the doctor by his arms. Dr. Bird shook them off contemptuously.

"Keep your filthy paws off me!" he cried. "I know when I'm bested, and I'll come quietly, but I won't be dragged."

The men looked at their leader for orders. From behind his light, the Russian studied his opponent. He gave vent to a stream of guttural Russian. The men fell back.

"For your information, Doctor," he said in a sneering tone. "I have told my men to follow you closely, gun in hand. At the slightest sign of hesitation, or at the first attempt to escape, they will fire. They are excellent shots."

"Lead on, Saranoff," was Dr. Bird's cheery comment.

With a shrug of his shoulders, the leader of the Young Labor party turned and made his way along the track toward the wharf. Dr. Bird looked anxiously ahead as they approached, fearing that Feodrovna Androvitch would be discerned in her hiding place. Saranoff correctly interpreted his gaze.

"Does der Herr Doktor Vogel eggspect somevun?" he asked in the voice which had first come over Dr. Bird's telephone. The doctor started and the Russian went on in the voice of the doctor's secretary. "I'm so glad you came, Dr. Bird. I am going to take you directly to the main base of our dearly beloved friend, Ivan Saranoff."

An expression that was a mixture of chagrin and relief spread over Dr.

Bird's face.

"Sold, by thunder!" he cried.

The Russian laughed sardonically and tramped on in silence. Tied to the Romney Creek wharf was a boat with powerful electric motors, driven by storage batteries. At a nudge from his captors, Dr. Bird took his place in the craft. It glided silently away down the creek toward the Chesapeake's mouth.

In the bay, the boat veered to the south and ran along the sh.o.r.e until the mouth of Bush River opened before them. It turned west up the river, coming to a halt at one of the occasional bits of high ground which bordered the river.

"We get off here, Doctor," said Saranoff. "My base, which you have wasted so much time seeking, lies within a hundred yards of this point. Before I take you there, you may be interested in watching us conceal our boat."

Before the doctor's surprised gaze, the edges of a huge box rose above the surface of the water, around the electric boat. The boat was raised and water could be heard running out of the box which held it.

When the box was drained, a man leaped in and made some adjustments. A cover, hinged on one side, swung over and closed the box tightly with the boat inside. Men closed clamps which held it in position. As they sprang to sh.o.r.e, the box sunk silently out of sight below the surface of the water.

"It is now beneath a foot of mud, Doctor," laughed the Russian, "and there is nothing to lead a searching party to suspect its existence.

Now I will take you to my base."

He led the way for a hundred yards over the ground. Before them loomed an old abandoned fisherman's shack. They entered to find merely a barren room. The Russian stepped to the far side and manipulated a hidden lever. Half of the floor slid to one side, disclosing a flight of steps leading down into Stygian darkness.

Flashlight in hand, Saranoff descended, Dr. Bird following closely on his heels. They went down twenty-one steps before the stairs came to an end. Above them, the floor could be heard closing. There was a sharp click and the cavern was flooded with light.

Dr. Bird looked around him with keen interest. Before him stood a static generator of gigantic proportions and of a totally unfamiliar design. Attached to it was an elliptic reflector of silvery metal, from which rose a short, stubby projector tube.

"I suppose, Dr. Saranoff--" began Dr. Bird.

"_Ivan_ Saranoff, if you please, Doctor," interrupted the Russian. "I have renounced the trumpery distinctions of your bourgeois civilization as far as I am concerned."

"I suppose, Ivan Saranoff," said Dr. Bird obligingly, "that this is the apparatus with which you send out a stream of negative particles."

"It is, Doctor. I had no idea that the nature of it would ever be discovered; at least not until I had changed the United States to a second Sahara desert. I reckoned without you. In point of fact, at the time that I built this device and started it in operation, I had not clashed with you. Now, I know that my plan is a failure. You have left data on which other men can work, have you not?"

"Surely."

"I would not have believed you had you said otherwise," replied the Russian with a sigh. "Yet this device has done much good. Now it shall be destroyed. It has not been a failure, for its destruction will accomplish both yours and that of your friend, Carnes."

"You haven't caught Carnes yet."

"That is easy. The same bait which caught you has caught him even more easily. I have a real sense of humor, Doctor, and before I went out of my way to bring you here, my plans were carefully laid. Mr. Carnes is now on his way here from Washington, lured by my voice. He is rushing, he thinks, to your rescue."

"What--"

Dr. Bird was suddenly silent.

"I am glad you comprehend my plan so readily, Doctor. Yes, indeed, Mr.

Carnes knows that I have captured you. He knows the exact location of this cavern and, more important, he knows the location of the power line which feeds my device when it is in operation. He also knows that there is stored in this cavern, fifty pounds of radite, your ultra-explosive. He knows that you are chained close to the explosive and that it is rigged with a detonator, connected with the power line.

In only one thing is he in error.

"He thinks, that if he can sever the power line before he attempts to penetrate the cavern, that the charge will be rendered harmless, and that you will be safe. In point of fact, the charge is set with an interrupter detonator which will explode as soon at the power line is severed. It pleases my sense of humor that it will be the hand of your faithful friend, Carnes, that will send you in fragments to eternity."

Beads of sweat shone on Dr. Bird's head as the Russian finished his speech, but his expression of amused interest did not change. Neither did his voice, when he spoke, betray any nervousness.

"And I presume that Carnes is also to be blown into bits by the explosion?" he asked.

"No, indeed, Doctor, that would frustrate one of the most humorous angles of the whole affair. He will cut the line at the base of a large rock, some two hundred yards from here, far enough away that he will not be seriously injured by the force of the explosion. Thus he will witness the explosion and realize what he has done. In order to be sure that he knows, as soon as he cuts the wire, my men will capture him. I, personally, will tell him of it. I wish to see his face when he realizes what he has unwittingly done."

"Then, I presume, you'll kill him?"

"I doubt it. I rather think I'll let him live. He should be useful to me."

"Carnes will never work for you!"

"With Feodrovna in my power, I rather think that Mr. Carnes will be an efficient and loyal servant. If not, he shall have the pleasure of watching me wreak my vengeance on her before he, himself, takes his last long trip."

"Saranoff," said Dr. Bird in a level voice, his piercing eyes boring straight into the Russian's, "I will remember this. Later, when you grovel at my feet and beg for mercy, it will be my friend, Operative Carnes, who will read your doom to you and choose the manner of it. I can promise you that your death will not be an easy one."

The Russian laughed, albeit the laugh had more of uneasiness than humor in it.

"When you have me in your power, Doctor, you may do as you like," he said, "but I do not fear dead men. In another two hours, you will be among the dead."

He turned to the three Russians who stood behind him.

"Seize him!" he cried.

The Russians leaped forward, but Dr. Bird was not caught napping. The first one went down like a felled tree before the doctor's fist. The other two came in cautiously. Dr. Bird sprang forward, feinting. As he leaped back, his foot struck a rod which Ivan Saranoff had thrust behind him. He staggered and fell. Before he could recover his balance, the two burly Russians were on him.