As the deadline approached, Tom pushed a button. The mighty hydraulic drivers throbbed into action, sending out their pulse waves across the continent!
[CHAPTER XVIII]
EARTHQUAKE ISLAND
Now came the hardest part of all for Tom and his companions—waiting to learn if the shock deflectors had succeeded in blotting out the enemy quake wave.
No one spoke. As the silence deepened inside the cave, the suspense became almost unbearable. Minutes passed.
"When will we know, skipper?" a crewman ventured at last.
"Soon, I hope," Tom replied tersely.
But the waiting seemed endless. Bud's eyes met Tom's. The flier grinned and held up crossed fingers, just as Tom had done to Mike Burrows the previous evening. Tom managed a feeble grin in response.
Suddenly the telephone shrilled, shattering the silence of the cave. Tom snatched it from the radioman's hands.