"Perfectly," was the answer, in Mr. Alcando's tones. "I have given it every test."

Then the voices again sunk to a low murmur.

[!-- H2 anchor --]

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—"