"I thought she might be useful, Doctor."

"Carnes, as you know, I dislike using women because they can't control their emotions or their expressions. She would just be in the way."

"It seems to me that she saved both our lives in Russia, Doctor, and but for her, you wouldn't have come out so well in your last adventure on the Aberdeen marshes."

"She did the first through uncontrolled emotions, and the second through a flagrant disobedience of my orders. No, don't tell her to come. Tell her not to come if she asks."

Carnes turned away, but hesitated.

"Doctor, I wish you'd let me have her come down here. I didn't trust her at first when you did, but she has proved her loyalty and worth.

Besides, I don't like the idea of leaving her unguarded in Washington with you and me down here, and with Haggerty coming down."

Dr. Bird looked thoughtful.

"There's something in that, Carnes," he reflected. "All right, tell her to come along, but remember, she is not in on this case. She is being brought here merely for safety, not to mix up in our work."

"Thanks, Doctor."

The detective returned in ten minutes with a worried expression.

"She wasn't in your office, Doctor," he reported.

"Who? Oh, Thelma. Where was she?"

"No one seems to know. She left yesterday afternoon and hasn't returned."

"Oh, well, since I am out of the city, I expect she decided to take a vacation. Women are always undependable. Did you get hold of the rest?"

"They'll be down at midnight, all but Davis. He'll come down in the morning."

"Good enough! Now, Colonel, if you'll have the officers who are going out to-morrow a.s.sembled, we'll divide the territory and make our plans for the search."

A week later, the situation was unchanged. Secret service operatives and soldiers from the Proving Ground had covered, foot by foot, square miles of territory south of the Proving Ground, but without result.

Not a single unexplainable thing had been found. Sensitive instruments sent down from the Bureau of Standards, instruments so sensitive that they would detect an electric light burning a mile away, had yielded no results. As a final measure, General Merton had ordered a dozen planes with steel-cylindered motors to the Proving Ground and they had repeatedly crisscrossed the suspected territory, but had acquired no static charge large enough to affect them. It was evident that Saranoff's device, if it existed, had been moved, or else was not in operation.

Also, to Carnes' openly expressed and Dr. Bird's secret worry, Thelma Andrews had not returned to the Bureau of Standards. The Russian girl, formerly known as Feodrovna Androvitch, a tool and follower of Ivan Saranoff, had acted with Carnes and the doctor in their long drawn-out fight with the arch-communist often enough to be a marked woman.

Urged by Carnes, Bolton, the head of the Secret Service, put a dozen of his best men on her trail, but they found nothing. She had disappeared as thoroughly as if the earth had opened and swallowed her up. At last, as the combing of the Aberdeen marshes yielded no results, Dr. Bird acceded to Carnes' request, and the detective left for Washington to take personal charge of the search. Dr. Bird sat alone in his quarters at the Officers' Club, futilely wracking his brains for a clue to his further procedure.

The telephone rang loudly. With a grunt, he took down the receiver.

A feminine voice spoke with a strong foreign accent.

"I vant der Herr Doktor Vogel, plees!"

"You want who? Oh, yes. Vogel--bird! This is Dr. Bird speaking."

The voice instantly lost both its foreign accent and its guttural quality.

"I thought so when you spoke, Doctor, but I wanted to make sure. This is Thelma Andrews."

"Where the devil have you been? Half the Secret Service is looking for you, including Carnes, who deserted me and is in Washington."

"He is? I'm sorry. Listen, Doctor, it's a long story and I can't go into details now. I got a clue on the day you left. As I couldn't get in touch with you, I followed it myself. I've located Saranoff's main base in the Bush River marshes."

"You have! Where is it?"

"It's underground and you've pa.s.sed over it a dozen times during the past week. It's unoccupied now and the machines are idle until your search is over. I know the way to it. If you'll join me now, we can get in and hopelessly wreck the device in a short time. To-morrow you can bring your men down here and take charge of it."

Dr. Bird's eyes glistened.

"I'll come at once, Thelma!" he cried. "Where are you?"

"I'm down on Romney Creek. Come down to the Water Impact Range below Michaelville, and I'll meet you at the wharf. You'd better come alone, because we'll have to sneak."

"Good for you!" cried the doctor. "I'll be down in an hour."

"All right, Doctor. I'll be waiting for you."

At Michaelville, Dr. Bird left his car and stepped on the scooter which ran on the narrow gauge track connecting the range house with the wharf on Romney Creek. He started it with no difficulty and it coughed away into the night. For three and a half miles, nothing broke the monotony of the trip. Dr. Bird, his hand on the throttle, kept his eyes on the twin ribbons of steel which slid along under the headlight. The road made a sharp turn and emerged from the thick wood through which it had been traveling. Hardly had the lights shot along the track in the new direction than Dr. Bird closed the throttle and applied the brakes rapidly. A heavy barricade of logs was piled across the track.

The doctor pressed home on the brake lever until the steel shoes screamed in protest, but no brakes could bring the heavy scooter to a stop as swiftly as was needful to avoid a crash. It was still traveling at a good rate of speed when it rammed into the barricade and overturned.

Dr. Bird was thrown clear of the wrecked scooter. He landed on soft mud beside the track. As he strove to rise, the beam of a flashlight struck him in the eyes and a guttural, sneering voice spoke through the darkness.

"Don't move, Dr. Bird. It will be useless and will only lead to your early death, a thing I should regret."

"Saranoff!" cried Dr. Bird.

"I am flattered, Doctor, that you know my voice. Yes, it is I, Ivan Saranoff, the man whom you have so often foiled. You drove me from America and tried to bar the road against my return, but I only laughed at your efforts. I returned here only for one purpose, to capture you and to compa.s.s your death."

Dr. Bird rose to his feet and laughed lightly.

"You've got me, Saranoff," he said, "but the game isn't played out yet. I represent an organization which won't end with my death, you know."

A series of expletives in guttural Russian answered him. In response to a command from their leader, two men came forward and searched the doctor quickly and expertly, removing the automatic pistol which he carried under his left armpit.

"As for your organization, as you call it--_pouf!_" said the Russian scornfully. "Carnes, a brainless fool who does only as you tell him, a few half-wits in the Bureau of Standards, some of them already in my pay, and one renegade girl. She shall learn what it means to betray the Soviets and their leader."

"You'll have to catch her first," replied Dr. Bird, a sardonic grin on his face.

"I have but to snap my fingers and she will come whining back, licking my hand and imploring mercy," boasted the Russian. "Bring him along!"