"I knew that if such a condition existed, the positively charged dust would be pulled down toward the source of the negative particle stream, which must, in many ways, resemble a cathode ray. That was why I wanted the behavior of the dust clouds watched and reported. What I did not foresee was that the iron and steel parts of the plane, accumulating a heavy negative charge, would be magnetized enough to slow down the motors and eventually wreck the ships." "We have had eight ships wrecked unexplainably within twenty miles of here, all of them to the south, during the past year," said Colonel Wesley. "It had slipped my notice. At any rate, the behavior of the ships this afternoon showed me that my theory is correct, and that some such device exists and is in active operation. Our next task is to locate it and destroy it." "You shall have every man on the Proving Ground!" cried Colonel Wesley. "Thank you. General Merton, will you detach three ships from the First Air Division by radio and have them report here? I want two pursuit ships and one bomber, with a rack of hundred-pound demolition bombs. All three must have duralumin cylinder blocks." "I'll do it at once, Doctor," the general agreed. "Thank you. Carnes, telephone Washington for me. Tell Dr. Burgess that I want Tracy, Fellows and Von Amburgh, with three more men down here by the next train. Also tell him to have Davis rig up a demagnetizer large enough to demagnetize the motors of a transport plane and bring it down here to fix up General Merton's ship. When you have finished that, get hold of Bolton and ask for a dozen secret service men. I want selected men with Haggerty in charge." "All right, Doctor. Shall I tell Miss Andrews to come down as well?" * * * * * Dr. Bird frowned. "Certainly not. Why would she come down here?" "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."