Don Luis was now within arm’s length of the thin curtain, and was apparently about to push it aside.

“Won’t you come outside,” suggested Tom, “and tell me the object of your call this evening?  It is too warm in here.”

“Gladly,” smiled the Mexican, letting go of the curtain, which he had just touched, and wheeling about.

“Hang the rascal!” muttered Tom, inwardly.  “Has he gotten wind of the fact that we have a stranger here?  Does Don Luis know all about the man?  Is he playing on my nerves at this moment?”

But Montez, with an appearance of being wholly interested in Tom Reade, went outside with him.  Harry placed campstools for the callers, while the young engineers threw themselves upon the ground.  Don Luis Montez, as usual, was to do the talking, while Dr. Tisco’s purpose in being present was to use his keen, snapping eyes in covertly studying the faces of the two Americans.

“I have called to say,” declared Don Luis, coming promptly to the point, “that within three days a party of American visitors will be here.  They come with a view to buying the mine, and I shall sell it to them at a very handsome profit.  Before we can deal with these Americans it will be absolutely necessary for me to have that report, signed by you both.  Moreover, you must both give me your word of honor that you will meet the Americans, and stand back of that report.  That you will do all in your power to make possible the sale of the mine.”

“We’ve discussed all of that before,” said Harry, dryly.

“And we shall yet require a little more time before we can give a too definite answer,” Tom broke in hastily, to head off his chum.

“But the time is short, caballeros,” Don Luis urged, a new light, however, gleaming in his eyes, for this was the first time that the young engineers had shown any likelihood of granting his wishes.

“A great deal can be decided upon in three days, Don Luis,” Tom went on, slowly.  “You will have to give us a little more time, and we will weigh everything carefully.”

“But you believe that you will be ready to meet my views?” Don Luis demanded, eagerly.

“I cannot see how our endorsement of your mine can be of any very great value to you,” Tom resumed.  “It is hardly likely that any of these capitalists who are coming have ever heard of us.  In any case, they are quite likely to feel that we are much too young to be able to form professional opinions of any value.”

“You give me your help in the matter,” coaxed Montez, “and I will attend to the rest.  More, caballeros; stand by me so well that I dispose of the mine, and I will promise you twenty thousand dollars, gold, apiece.”

“That is a lot of money,” Reade nodded, thoughtfully.  “But there are other considerations, too.”