“They’re trying to wreck our setup, aren’t they?” Bud retorted.  “Think of the destruction they’ve caused already!  Do you want to stand by and see Enterprises destroyed too?”

“Bud’s right,” Hank Sterling spoke up quietly.  “Take a look at this.”

He beckoned them over to another corner of the cave and pointed to a series of notations, crudely scrawled in white chalk on the cave wall.  Half hidden behind a clump of rock, they would have escaped casual notice.

Tom read them and gave an angry gasp.  A list of places and dates, already checked off, showed the quakes that had occurred so far.  The last notation, not yet checked, said:  SWIFT ENTERPRISES and was dated five days ahead.

“Okay, that’s all the convincing I need!” Tom said grimly.

He issued quick orders.  Hank and Arv were to rush back to the Sea Hound, get an underwater pump from the gear carried aboard, and install it just off the beach.  From there, they were to run a pipe line up into the cave, using special plastic tubing which hooked together in a jiffy.

“Cover the piping with sand and gravel, so it won’t be noticed,” Tom added.  “In the meantime, Bud and I will go to work on this setup here.”

“Aye-aye, skipper!” Hank and Arv responded.

As they hurried out through the tunnel, Tom and Bud set to work with the tools they had brought along.  The diesel was partly dismantled, sand poured into its fuel feed, and the generator windings ripped out.  The boys then tore off and tangled all wiring leads to the electrical equipment, took apart much of the equipment itself, and smashed the control panel.

“Boy, if those Brungarian creeps get this setup working again, they’re really geniuses!” Bud said as he and Tom paused a second.

“This is only the beginning, pal!” Tom said.  “Let’s tackle the machine!”

The huge earthquake device was a far more difficult proposition to disable.  Its heavy structural parts had to be disassembled or pried apart, one by one.  Both boys were streaked with sweat as they finished.

By this time, Hank and Arv had the piping installed halfway into the tunnel.  Spurred on as if by a sixth sense of danger, Tom told them to go back to the beach and get the pump working while he and Bud connected the few remaining pipe lengths into the machine room.

Minutes later, their job done, Tom and Bud rushed out to the mouth of the cave and waved their flashlights.  Soon the water could be heard boiling through the pipeline.  It gushed out with a roar, flooding the machine room.

“Let’s go!” Tom cried, yanking Bud’s arm.

As they reached the beach and joined Hank and Arv, Tom’s keen ears picked up the drone of a plane somewhere in the darkness.

He gave a yell of alarm and pointed skyward.  A ghostlike jet came zooming into view, boring straight toward them.  All four broke into a mad dash for the seacopter.