Several times after this the Spaniard went off by himself, to make simple moving picture views with the little camera.  But, whether or not he took along the curious brass-bound box, with the metal projections, which he said was an alarm clock, was something Blake or Joe could not discover.  For Blake had told Joe of Alcando’s confession.

Certainly if Alcando did take his model with him, he did not wind it up until leaving the boys, for no ticking sound came from the case.

The Canal was now as it had been before the big slide.  Vessels were passing to and fro, though in some parts of the waterway much finishing work remained to be done.  Blake and Joe took some views of this, and also “filmed” the passage of the various ships to make their pictures of wider appeal when they would be shown at the Panama Exposition.  Mr. Alcando did his share, and, for a time seemed to show a great interest in his work, so that Blake had hopes the Spaniard would really become a good operator.  But something was always lacking, and it was not altogether effort on the part of the pupil.

The time was approaching when Blake and Joe must bring their work to an end.  They had accomplished what they set out to do, and word came back from New York, where their films had been sent for development, that they were among the best the boys had ever taken.

“Well, I will soon be leaving you,” said Mr. Alcando to the chums, one day.  “I have heard from my railroad firm, and they are anxious for me to come back and begin making pictures there.”

“His friends are going to be sadly disappointed in him,” thought Blake.  “It’s too bad.  He’ll make a failure of those views.  Well, if he does they may send for Joe and me, and that will be so much more business for us, though I’m sorry to see him make a fizzle of it.”

But Mr. Alcando appeared to have no fears on his own account.  He was cheerfully optimistic.

“I shall want several cameras, of different kinds,” he said to the boys.  “Perhaps you can recommend to me where to get some.”

“Yes,” spoke Joe.  “We’ll help you pick them out if you are going back to New York.”

“I am not so sure of that,” the Spaniard said.  “I will know in a few days when I hear from my railroad friends.  I expect a letter shortly.”

There was some little delay in getting the pictures Blake wanted of the Gatun Dam.  Certain work had to be done, and Blake wanted to show the complete and finished structure.  So he decided to wait.

About a week after the above conversation with Mr. Alcando, the Spaniard came to the boys, waving an open letter in his hand.  The mail had just come in, bringing missives to Blake and Joe.  Some were of a business nature, but for each boy there was an envelope, square and of delicate tint—­such stationery as no business man uses.  But we need not concern ourselves with that.  We all have our secrets.