he doctor's car tore off to the west. Near Upper Marlboro, he met the convoy of trucks and led them to the selected spot. The trucks were unloaded and the apparatus laid out. Attached to a huge transformer were a dozen strange-looking projectors. What puzzled Carnes most was a huge built-up steel bar wound about with heavy cable. Dr. Bird had this bar erected on a truck and located it with great exactness. The projectors were set up in a battery just east of the bar.
"How about power?" asked the doctor.
"We'll have it in five minutes," replied one of the men. "A power transmission line carrying twenty-two thousand passes within two hundred yards of here. We are phoning now to have the power cut off. As soon as the line is dead we'll cut it and bring the ends here."
The electrician was good at his word. In five minutes the power line had been cut and cables spliced to the ends. The cables were brought to the doctor's apparatus and the main lines were rigged to the ends of the cable wound around the bar. In parallel on taps, the projectors were connected. Huge oil-switches were placed in both lines.
"All ready, Doctor," reported the electrician.
"Good work, Avent. He'll be here soon, I fancy."
A car whirled up and a man leaped out with a surveyor's rod. He set it up on the ground while a companion watched through binoculars. He moved it a hundred yards to the north and then back twenty. When he was satisfied he turned to Dr. Bird.
"The direction of movement has not changed," he said. "The path will pass under this stake."
Under the doctor's supervision, the truck carrying the bar moved forward until it stood over the surveyor's stake. The battery of projectors moved to a new location a few feet east of the rod. Other cars came racing up.
"He's less than half a mile away, Doctor!" cried Jones.