“But I was to throw the blame on innocent parties if I could,” the Spaniard went on, in his confession.  “Also I was to select a means of causing the explosion that would not easily be detected.  I selected moving pictures as the simplest means.  I knew that some were to be made of the Canal for Government use, and I thought if I got in with the moving picture operators I would have a good chance, and good excuse, for approaching the dam without being suspected.  After I had accomplished what I set out to do I could, I thought, let suspicion rest on the camera men.

“So I laid my plans.  I learned that Mr. Hadley’s firm had received the contract to make the views, and, by inquiries, through spies, I learned who their principal operators were.  It was then I came to you boys,” he said.  “Ashamed as I am to confess it, it was my plan to have the blame fall on you.”

Blake and Joe gasped.

“But when you saved my life at the broken bridge that time, of course I would not dream of such a dastardly trick,” the Spaniard resumed.  “I had to make other plans.  I tried to get out of it altogether, but that man would not let me.  So I decided to sacrifice myself.  I would myself blow up the dam, or, rather, make a little explosion that would scare prospective shippers.  I did not care what became of me as long as I did not implicate you.  I could not do that.

“So I changed my plans.  Confederates supplied the dynamite, and I got this clock-work, in the brass-bound box, to set it off by means of electrical wires.  I planned to be far away when it happened, but I would have left a written confession that would have put the blame where it belonged.

“I kept the battery box connections and clockwork inside the small camera I carried.  Tonight all was in readiness.  The dynamite was planted, and I set the mechanism.  But something went wrong with it.  There was too much of a delay.  I came back to change the timer.  I broke the string connections you made, and—­I was caught by the camera.  The news had, somehow, leaked out, and I was caught.  Well, perhaps it is better so,” and he shrugged his shoulders with seeming indifference.

“But please believe me when I say that no harm would have come to you boys,” he went on earnestly, “nor would the dam have been greatly damaged.

“It was all a terrible plot in which I became involved, not all through my own fault,” went on the Spaniard, dramatically.  “As soon as I met you boys, after you had saved my life, I repented of my part, but I could not withdraw.  The plans of this scoundrel —­yes, I must call him so, though perhaps I am as great—­his plans called for finding out something about the big guns that protect the Canal.  Only I was not able to do that, though he ordered me to in a letter I think you saw.”

Blake nodded.  He and Joe were beginning to understand many strange things.