"Do you mean by an earthquake?" asked Blake, breaking in on his chum's words.
"No, I don't take any stock in their earthquake theories," the captain answered. "That's all bosh! It's dynamite."
"Dynamite!" cried Joe and Blake in a breath.
"Yes, there are rumors, so persistent that they cannot be denied, to the effect that the dam is to be blown up some night."
"Blown up!" cried Blake and Joe again.
"That's the rumor," continued Captain Wiltsey. "I don't wonder you are astonished. I was myself when I heard it. But I've come to get you boys to help us out."
"How can we help?" asked Blake. "Not that we won't do all we can," he added hastily, "but I should think you'd need Secret Service men, detectives, and all that sort of help."
"We'll have enough of that help," went on the tug boat commander, who was also an employee of the commission that built the Canal. "But we need the peculiar help you boys can give us with your cameras."
"You mean to take moving pictures of the blowing up of the dam?" asked Joe.
"Well, there won't be any blowing up, if we can help it," spoke the captain, grimly. "But we want to photograph the attempt if it goes that far. Have you any flashlight powder?"