“So do I,” confessed his chum.

They were to make the entire trip through the Canal as guests of Uncle Sam, the Government having acceded to Mr. Hadley’s request, as the completed films were to form part of the official exhibit at the exposition in California later on.

“Whew, but it is hot!” exclaimed Joe, after he and Blake had looked over their possessions, to make sure they were forgetting nothing for their trip next day.

“Yes,” agreed Blake.  “Let’s go out on the balcony for a breath of air.”

Their room opened on a small balcony which faced the beach.  Mr. Alcando had a room two or three apartments farther along the corridor, and his, too, had a small balcony attached.  As Blake and Joe went out on theirs they saw, in the faint light of a crescent and much-clouded moon, two figures on the balcony opening from the Spaniard’s room.

“He has company,” said Joe, in a low voice.

“Yes,” agreed Blake.  “I wonder who it is?  He said all of his friends had left the hotel.  He must have met some new ones.”

It was very still that night, the only sounds being the low boom and hiss of the surf as it rushed up the beach.  And gradually, to Joe and Blake, came the murmur of voices from the Spaniard’s balcony.  At first they were low, and it seemed to the boys, though neither expressed the thought, that the conference was a secret one.  Then, clearly across the intervening space, came the words: 

“Are you sure the machine works right?”

“Perfectly,” was the answer, in Mr. Alcando’s tones.  “I have given it every test.”

Then the voices again sunk to a low murmur.

CHAPTER XI

ALONG THE CANAL

“Blake, did you hear that?” asked Joe, after a pause, during which he and his chum could hear the low buzz of conversation from the other balcony.

“Yes, I heard it.  What of it?”

“Well, nothing that I know of, and yet—­”

“Yet you’re more suspicious than I was,” broke in Blake.  “I don’t see why.”

“I hardly know myself,” admitted Joe.  “Yet, somehow, that ticking box, and what you saw in that letter—­”

“Oh, nonsense!” interrupted Blake.  “Don’t imagine too much.  You think that curious box is some attachment for a moving picture camera; do you?”

“Well, it might be, and—­”

“And you’re afraid he will get ahead of you in your invention of a focus tube; aren’t you?” continued Blake, not giving his companion a chance to finish what he started to say.  For Joe had recently happened to hit on a new idea of a focusing tube for a moving picture camera, and had applied for a patent on it.  But there was some complication and his papers had not yet been granted.  He was in fear lest someone would be granted a similar patent before he received his.

“Oh, I don’t know as I’m afraid of that,” Joe answered slowly.