"One of us did him up this morning." "Go ahead, Tom!" Reade led the way in the darkness.

They skirted the road, though keeping a sharp lookout.
"There are the lights of the mule-train ahead," whispered Tom.
"Now, we're close enough to see things, for there is _El Sombrero_ just ahead." "What's the game, anyway ?" whispered Harry.
"Surely you guess," protested Tom.
"Why, it seems that Don Luis is having ore from another mine brought down in the dead of the night." "Yes, and a lot of it," Tom went on.

"Did you notice how much rich ore there was in each tunnel to-day?
And did you notice, too, that when blasts were made with us looking on, no ore worthy of the name was dug loose?
Don Luis has been spending a lot of money for ore with which to salt his own mine!" "Salting" a mine consists of putting the gold into a mine to be removed.

Such salting gives a worthless mine the appearance of being a very rich one.
"But why should Don Luis want to salt his own mine ?" muttered Harry.
"So that he can sell it, of course!" "But he doesn't want to sell." "He says he doesn't," Tom retorted, with scorn.

"This afternoon, you remember, he got me to copy a report in English about his mine and then he wanted us to sign the report as engineers.