"How does it work, Tom?" Hank asked. "Dual-control spheres on top," Tom explained, "will receive by radio signal the pulse frequency computed in Washington." He added that inside each sphere was a "pulsemaker." This would produce changes in the pressure of the hydraulic fluid by affecting the kinetic energy of the fluid's atoms. The pressure changes would then be enormously magnified in the four hydraulic output drivers. When the unit was embedded in rock, underground, the huge pistons would send out counter shock waves through the earth's crust to neutralize the enemy waves. "Wow!" Hank Sterling was breathless at the sheer scope of the young scientist's newest invention. "I'll get hot on the job right away." After forty-eight hours of round-the-clock work, the equipment was ready. Tom conferred by telephone with both Dr. Miles in the Bureau of Mines and Bernt Ahlgren in the Pentagon. He had already chosen the spots for the detector-transmitter check points. Tom told the men that he believed the best spot for the Quakelizor itself was on a certain government reservation in Colorado. A deep underground cave there would provide a perfect site. "We'll be close enough to the San Andreas fault to prevent a really huge-scale disaster," Tom explained. "And the Rocky Mountain structure will give us a good bedrock medium for shooting out waves anywhere across the continent." Dr. Miles and Ahlgren agreed enthusiastically. Tom and the two scientists spoke over a three-way telephone hookup--with automatic scramblers to counter the danger of enemy monitors--laying plans to install the equipment. Ahlgren agreed to fly a technical crew out to the spot in Colorado which Tom had named. The next day, Tom, Hank, and several top Enterprises' engineers, including Art Wiltessa, took off in the _Sky Queen_. This was Tom's huge atomic-powered Flying Lab. The massive plane flew at supersonic speeds and was equipped with jet lifters for vertical take-off or hovering. A Whirling Duck heliplane, loaded with communications equipment, accompanied the _Sky Queen_. In little more than an hour, the two craft touched down in a rugged Colorado canyon. The government technical crew was already on hand. "Glad to know you," Tom said, shaking hands with the engineer in charge. He introduced his own men and added, "Better roll up your sleeves. This job is going to take plenty of oomph!" The parts of the Quakelizor were unloaded from the _Sky Queen_ onto dollies. Then the group, armed with bull's-eye lanterns, flashlights, and walkie-talkies, hauled the parts by tractor into the cave. "Okay. Now let's pick out the spot for embedding the unit," Tom said. The men had no sooner begun to look around the huge underground chamber when a fearsome growl rumbled through the cave. Everyone whirled about and the next instant froze in horror. A huge bear reared up in the mouth of the cave! The monster snarled and blinked its yellow eyes in the glare of lights.