“Well, it must be that—­or something,” insisted Blake.  “You hear Alcando and someone else talking about a machine, and you at once jump to the conclusion that it’s a camera.”

“No, I don’t!” exclaimed Joe.  He did not continue the conversation along that line, but he was doing some hard thinking.

Later that evening, when Mr. Alcando called at the room of the two chums to bid them goodnight, he made no mention of his visitor on the balcony.  Nor did Blake or Joe question him.

“And we start up the Canal in the morning?” asked the Spaniard.

“Yes, and we’ll make the first pictures going through the Gatun locks,” decided Blake.

“Good!  I am anxious to try my hand!” said their “pupil.”

With their baggage, valises, trunks, cameras, boxes of undeveloped film, other boxes to hold the exposed reels of sensitive celluloid, and many other things, the moving picture boys and Mr. Alcando went aboard the government tug Nama the next morning.  With the exception of some Army engineers making a trip of inspection, they were the only passengers.

“Well, are you all ready, boys?” asked the captain, for he had been instructed by his superiors to show every courtesy and attention to our heroes.  In a sense they were working for Uncle Sam.

“All ready,” answered Blake.

“Then we’ll start,” was the reply.  “I guess—­”

“Oh, one moment, I beg of you!” cried Mr. Alcando.  “I see a friend coming with a message to me,” and he pointed along the pier, where the tug was tied.  Coming on the run was a man who bore every appearance of being a Spaniard.

“You are late,” complained Mr. Alcando, as the runner handed him a letter.  “You almost delayed my good friend, the captain of this tug.”

“I could not help it,” was the answer.  “I did not receive it myself until a few minutes ago.  It came by cable.  So you are off?”

“We are off!” answered Mr. Alcando.

Then the other spoke in Spanish, and later on Blake, who undertook the study of that language so as to make himself understood in a few simple phrases knew what it was that the two men said.  For the runner asked: 

“You will not fail us?”

“I will not fail—­if I have to sacrifice myself,” was the answer of Mr. Alcando, and then with a wave of his hand the other went back up the pier.

“All right?” again asked Captain Watson.

“All right, my dear sir, I am sorry to have delayed you,” answered Mr. Alcando with more than his usual politeness.

“A little delay doesn’t matter.  I am at your service,” the commander said.  “Well, now we’ll start.”

If either Blake or Joe felt any surprise over the hurried visit, at the last minute, of Mr. Alcando’s friend, they said nothing to each other about it.  Besides, they had other matters to think of just then, since now their real moving picture work was about to begin.