“Too bad.”
Once inside the submarine again, the boys refreshed themselves with a lunch from the food locker. As Tom finished a cup of hot chocolate, he said: “We’re only about fifty miles west of Lazar Canyon. It’s four thousand feet deep at that point.”
Bud munched a sandwich. “I get it,” he said. “Our deep-sea fisherman is thinking of going down there.”
Tom grinned. “You’re looking into your crystal ball again, pal. I was just thinking the canyon might be a good spot to solve the problem of the phantom bottom.”
“You mentioned that before,” Bud said. “It sounds like something that might go right through to the other side of the world. What is this thing, anyway?”
Tom laughed. “Well, you asked for it, so here 134 TOM SWIFT AND HIS JETMARINE
goes. For several years, when fathometers on ships have been taking depth soundings, they often pick up a false bottom before getting the actual depth. This phantom bottom is like a mass that lies somewhere between the real bottom and the surface.”
“What’s the mass made of?”
“Some scientists say fish,” Tom explained. “Others *hrimp and still others squid. I’m a ‘squid’ man myself.”
Bud looked blank but interested. “Why?”
“Because the phantom bottom can change its position in the span of one day from three hundred to eighteen hundred feet or more,” Tom added.
“So?”
“The squid are better able than fish or shrimp to make this great shift,” Tom answered. “Change in pressure doesn’t bother them.”
“I see,” said Bud.
“With this sub,” Tom went on, “we can go to any depth and find out for ourselves.”