"If we assume that it came from the bottom, it must have been traveling at least sixty miles an hour when it broke surface," said Terry.
"But can a whale swim sixty miles an hour?"
"No," said Terry.
Tony hesitated, opened his mouth, closed it, and went away.
Terry returned to the changing of the submarine horn. Sound has its own tricks underwater. If you know something about them you can produce some remarkable results. A deliberately made underwater signal can be heard through an unbelievable number of thousands of miles of seawater. But, except through a yet untested fish-driving paddle, Terry had never heard of fish being herded by sound. Still, fish can be stunned or killed by concussions. They have been known to be made unconscious by the noise of a very near submarine bell. It wasn't unreasonable that a specific loud noise could make a barrier no fish would try to cross. But there were still some parts of last night's events that did not fit into any rational explanation.
Davis came over to Terry.
"I think," he said, "that we may have missed a lot of information by not having submarine ears before. There may have been all sorts of noises we could have heard."
"Possibly," agreed Terry.
"We're more or less in the position of savages faced with phenomena they don't understand," said Davis vexedly. "The simple problems of savages range from what produces thunder to what makes people die of disease. Savages come up with ideas of gods or devils doing such things for reasons of their own. We can't accept ideas of that sort, of course!"
"No," agreed Terry, "we can't."