He turned to leave the cabin, but, as he did so, Captain Wiltsey entered.  He paid no attention to the Spaniard, but, addressing Blake and Joe said: 

“Boys, I have a little task for you.  Have you any flash-light powder?”

“Flash-light powder?  Yes, we have some,” Blake said.  “But we can’t use it for moving pictures.  It doesn’t last long enough.”

“Perhaps it will last long enough for what I want,” the captain said.

“If you’ll excuse me, I’ll go back and get the camera I was so careless as to leave out,” spoke Mr. Alcando.

“I’m glad he’s gone,” Captain Wiltsey said, as the cabin door closed.  “I’d rather tell this to just you boys.  I’ve just had a queer warning,” he said.

“A warning?” repeated Joe.

“Yes, about Gatun Dam.  There’s a rumor that it is going to be destroyed!”

CHAPTER XXIII

THE FLASHLIGHT

For an instant the moving picture boys could hardly grasp the meaning of the fateful words spoken by Captain Wiltsey.  But it needed only a look at his face to tell that he was laboring under great excitement.

“The Gatun Dam to be destroyed,” repeated Joe.  “Then we’d better get—­”

“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?”

“Yes,” Blake answered.  “Or, if not, we can make some with materials we can easily get.  But you can’t make more than a picture or two by flashlight.”

“Couldn’t you if you had a very big flashlight that would last for several minutes?”

“Yes, I suppose so.”

“Well, then, figure on that.”

“But I don’t understand it all,” objected Blake, and Joe, too, looked his wonder.  Both were seeking a reason why the captain had said he was glad Mr. Alcando had gone out to get the camera he had forgotten.