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 moving picture boys.

"Well,—I—er,—I—," stammered Blake. Somewhat to his own surprise he did find himself harboring new suspicions against Mr. Alcando, but they had never before taken this form. As for Joe, he blushed to recall that he had, in the past, also been somewhat suspicious of the Spaniard. But now the man's frank manner of speaking had disarmed all that.

"Dynamite, eh!" exclaimed the captain. "I'd just like to see any one try it. This canal is better guarded than you think, my friend," and he looked meaningly at the other.

"Oh, I have no doubt that is so," was the quick response. "But it seems such a simple matter for one to do a great damage to it. Possibly the indifference to guarding it is but seeming only."

"That's what it is!" went on Captain Watson. "Dynamite! Huh! I'd like to see someone try it!" He meant, of course, that he would not like to see this done, but that was his sarcastic manner of speaking.

"What do you think of him, anyhow?" asked Joe of Blake a little later when they were putting away their cameras, having taken all the views they wanted.

"I don't know what to say, Joe," was the slow answer. "I did think there was something queer about Alcando, but I guess I was wrong. It gave me a shock, though, to hear him speak so about the Canal."

"The same here. But he's a nice chap just the same, and he certainly shows an interest in moving pictures."

"That's right. We're getting some good ones, too."

The work in Culebra Cut, though nearly finished, was still in such a state of progress that many interesting films could be made of it, and this the boys proposed to do, arranging to stay a week or more at the place which, more than any other, had made trouble for the canal builders.

"Well, it surely is a great piece of work!" exclaimed Blake, as he and Joe, with Mr. Alcando and Captain Watson, went to the top of Gold Hill one day. They were on the highest point of the small mountain through which the cut had to be dug.

"It is a wonderful piece of work," the captain said, as Blake and Joe packed up the cameras they had been using. "Think of it—a cut nine miles long, with an average depth of one hundred and twenty feet, and in some places the sides are five hundred feet above the bottom, which is, at no point, less than three hundred feet in width. A big pile of dirt had to be taken out of here, boys."

"Yes, and more dirt will have to be," said Mr. Alcando.

"What do you mean?" asked the tug commander quickly, and rather sharply.

"I mean that more slides are likely to occur; are they not?"

"Yes, worse luck!" growled the captain. "There have been two or three small ones in the past few weeks, and the worst of it is that they generally herald larger ones."

"Yes, that's what I meant," the Spaniard went on.

"And it's what we heard," spoke Blake. "We expect to get some moving pictures of a big slide if one occurs."

"Not that we want it to," explained Joe quickly.

"I understand," the captain went on with a smile. "But if it is going to happen you want to be here."

"Exactly," Blake said. "We want to show the people what a slide in Culebra looks like, and what it means, in hard work, to get rid of it."

"Well, it's hard work all right," the captain admitted, "though now that the water is in, and we can use scows and dredges, instead of railroad cars, we can get rid of the dirt easier. You boys should have been here when the cut was being dug, before the water was let in."

"I wish we had been," Blake said. "We could have gotten some dandy pictures."

"That's what you could," went on the captain. "It was like looking at a lot of ants through a magnifying glass. Big mouthfuls of dirt were being bitten out of the hill by steam shovels, loaded on to cars and the trains of cars were pulled twelve miles away to the dumping ground. There the earth was disposed of, and back came the trains for more. And with thousands of men working, blasts being sent off every minute or so, the puffing of engines, the tooting of whistles, the creaking of derricks and steam shovels—why it was something worth seeing!"

"Sorry we missed it," Joe said. "But maybe we'll get some pictures just as good."

"It won't be anything like that—not even if there's a big slide," the captain said, shaking his head doubtfully.

Though the Canal was practically finished, and open to some vessels, there was much that yet remained to be done upon it, and this work Blake and Joe, with Mr. Alcando to help them at the cameras, filmed each day. Reel after reel of the sensitive celluloid was exposed, packed in light-tight boxes and sent North for development and printing. At times when they remained in Culebra Cut, which they did for two weeks, instead of one, fresh unexposed films were received from New York, being brought along the Canal by Government boats, for, as I have explained, the boys were semi-official characters now.

Mr. Alcando was rapidly becoming expert in handling a moving picture camera, and often he went out alone to film some simple scene.

"I wonder how our films are coming out?" asked Blake one day, after a fresh supply Of reels had been received. "We haven't heard whether Mr. Hadley likes our work or not?"

"Hard to tell," Joe responded. But they knew a few days later, for a letter came praising most highly the work of the boys and, incidentally, that of Mr. Alcando.

"You are doing fine!" Mr. Hadley wrote. "Keep it up. The pictures will make a sensation. Don't forget to film the slide if one occurs."

"Of course we'll get that," Joe said, as he looked up at the frowning sides of Culebra Cut. "Only it doesn't seem as if one was going to happen while we're here."

"I hope it never does," declared Captain Watson, solemnly.

As the boys wanted to make pictures along the whole length of the Canal, they decided to go on through the Pedro Miguel and Miraflores locks, to the Pacific Ocean, thus making a complete trip and then come back to Culebra. Of course no one could tell when a slide would occur, and they had to take chances of filming it.

Their trip to Pedro Miguel was devoid of incident. At those locks, instead of "going up stairs" they went down, the level gradually falling so their boat came nearer to the surface of the Pacific. A mile and a half farther on they would reach Miraflores.

The tug had approached the central pier, to which it was tied, awaiting the services of the electrical locomotives, when back of them came a steamer, one of the first foreign vessels to apply to make the trip through the Isthmus.

"That fellow is coming a little too close to me for comfort," Captain Watson observed as he watched the approaching vessel.

Blake and Joe, who were standing near the commander at the pilot house, saw Mr. Alcando come up the companionway and stand on deck, staring at the big steamer. A little breeze, succeeding a dead calm, ruffled a flag at the stern of the steamer, and the boys saw the Brazilian colors flutter in the wind. At the same moment Mr. Alcando waved his hand, seemingly to someone on the steamer's deck.

"Look out where you're going!" suddenly yelled Captain Watson. Hardly had he shouted than the steamer veered quickly to one side, and then came a crash as the tug heeled over, grinding against the concrete side of the central pier.

"We're being crushed!" yelled Blake.