“Farnum,” he said, “I understand that something is to happen, to-night, that you and I ought to know.”

“What is it?” asked the boatbuilder, alive with curiosity.

“I’ll give you a chance to find out, to-night, but you must pledge me your word that you won’t breathe a word of this, until afterwards, to anyone, not even to Pollard.  Just come along and learn what you learn, then act as you please.  Will you agree to that?”

“Yes,” promised Mr. Farnum.

“Good enough.  Then be at—­” Broughton Emerson followed with directions for late the coming evening.  He did not explain who was to be spied upon, or anything of the nature of the business, though he did add: 

“Don’t be surprised, Farnum, no matter whom you see me with.  It’s all a part of the night’s walk.  Just follow us both, without letting your presence be known at any stage.  I know this all sounds mysterious, but believe me, it’s going to be vastly worth your while.”

The remainder of the afternoon the boatbuilder’s heart was, somehow, heavy with undefined dread as to what he was to learn that night.

In the middle of the afternoon, Don Melville, with the aid of one of his father’s Italian workmen, laid the last stone in the edifice of trickery that he was building for the crushing of Jack Benson.

“Jack was coming down the street from the village, when his steps were arrested by the sound of a sharp: 

“Hist!”

Turning, he saw an Italian workman, beckoning mysteriously.  Jack went curiously up to him.

“I have message for you—­you alone,” whispered the Italian, speaking fairly good English.  “You are in danger of great meanness.  One of your enemies plots it.”

“You’re one of the Melville workmen, aren’t you?” asked Captain Jack, looking curiously at the fellow.

“Yes, and you have bad, wicked enemies over at our place.”

“I guess that may be true enough,” smiled Jack, grimly.

“Some of us are bad over there, and some honest,” went on the Italian.  “Some of us hate much to see dirty work done, and I have friend who works also for Melville.  My friend knows all about what Don would do against you.  It is wicked—­very.  Meet my friend, to-night, at nine o’clock, and he will tell you all—­everything.  I cannot tell you now.  But you will meet my friend?”

“Yes, I guess I will,” nodded Jack Benson.

“But you must go alone; not tell your odder friends.  Until you have seen my friend you must keep all this gr-reat secret.”

After some further talk Jack Benson agreed to all this.  The Italian seemed wholly honest and earnest.  Moreover, he appeared as though greatly troubled and anxious to save the submarine boy from some unusually mean trick.

So Jack Benson walked on, thinking deeply and wondering much.  He had no suspicion of any trap against him in the person of this seemingly very honest Italian, and so Don Melville had succeeded in laying the last wire of his despicable plan.