"We are about opposite the place where we left that sub last night. I fancy that Saranoff will operate from there, for it didn't move during the last half hour we watched it. We'll go back inland a mile or two and spread out. I have no idea how far his radiations will affect the electroscopes, but we'll try four hundred-yard intervals to start. That will enable us to cover a line twelve miles long." He picked up a megaphone and spoke to the line of cars behind him. "Take up four hundred yard intervals when we spread out," he said. "Every man keep his headphone on and listen for orders. Follow my car until it stops, then turn north and south and drop your men at intervals." He reentered the car and led the way back for two miles. He halted his car at a crossroad. The cars following him turned and went to the north and south. Besides Carnes and the doctor, the car held two men from the Bureau. As they climbed out, Carnes saw that one of them carried a portable radio sending set, while the other bore an electroscope and a rubber rod. The radio operator set up his device, while the other man rubbed his coat sleeve briskly with the hard rubber and then touched the ball of the electroscope with it. The two bits of gold-leaf spread out. "While we're waiting, I'll explain something of this to you, Carnes," said the doctor. "At four hundred-yard intervals are men with electroscopes like this one. My attempt to locate Saranoff by means of wave detectors was a failure. That proved that the ray he was using is not of the wave type. The other common ray is the cathode ray type which does not consist of vibrations but of a stream of electrons, negative particles of electricity, traveling in straight lines of high velocity. He must be knocking loose some of the electrons when he collapses the atoms. The rate of discharge of these electroscopes will give us a clue to the nearness of his device." * * * * * "Once you locate him, how do you propose to attack him?" "The obvious method, that of using his own ray against him, fell down. However, in attempting to produce it, I stumbled on another weapon which may be equally effective. I am going to try to use an exact opposite of his ray. The cathode ray, when properly used, will bombard the atoms and knock electrons loose. I perfected last night a device on which I have been working for months. It is a super-cathode ray. I tested it on the yellow powder and find that I can successfully reverse Saranoff's process. He can contract matter together until it occupies less than one one-thousandth of its original volume. My ray will destroy this effect and restore matter to something like its original condition." "And the effect will be?"