ant no more slides."

"But some are predicted," Blake remarked.

"Yes, I know they say they come every so often. But now it would
take a pretty big one to do much damage. We have nearly tamed
Culebra."

"If there came a big slide here it would block the Canal,"
observed Mr. Alcando, speculatively.

"Yes, but what would cause a slide?" asked the captain.

"Dynamite could do it," was the low-voiced answer.

"Dynamite? Yes, but that is guarded against," the commander said.
"We are taking no chances. Now, boys, you get a good view of
Culebra," and he pointed ahead. Blake and Joe were soon busy with
their cameras, making different sets of views.

"Hand me that other roll of film; will you, please?" asked Blake
of the Spaniard, who was helping them. "Mine is used up."

As Mr. Alcando passed over the box he muttered, though possibly he
was unaware of it:

"Yes, dynamite here, or at the dam, would do the work."

"What--what's that?" cried Blake, in surprise.

CHAPTER XVI

THE COLLISION

Judging by Mr. Alcando's manner no one would have thought he had
said anything out of the ordinary. But both Blake and Joe had
heard his low-voiced words, and both stared aghast at him.

"What's that you said?" asked Blake, wondering whether he had
caught the words aright.

"Dynamite!" exclaimed Joe, and then Blake knew he had made no
mistake.

Somewhat to the surprise of himself and his chum the Spaniard
smiled.

"I was speaking in the abstract, of course," he said. "I have a
habit of speaking aloud when I think. I merely remarked that a
charge of dynamite, here in Culebra Cut, or at Gatun Dam, would so
damage the Canal that it might be out of business for years."

"You don't mean to say that you know of any one who would do such
a thing!" cried Blake, holding the box of unexposed film that the
Spaniard had given him.

"Of course not, my dear fellow. I was speaking in the abstract, I
tell you. It occurred to me how easy it would be for some enemy to
so place a charge of explosive. I don't see why the Canal is not
better guarded. You Americans are too trusting!"

"What's that?" asked Captain Watson, coming up at this juncture.

"I was merely speaking to the boys about how easy it would be to
put a charge of dynamite here in the cut, or at the dam, and
damage the Canal," explained Mr. Alcando. "I believe they thought
I meant to do it," he added with a laugh, as he glanced at the
serious faces of the two movin