"Ha-ho-hum!" yawned Pedro Gato, audibly.

Tom raised his head, studying their immediate surroundings. He soon fancied he saw a safe way of slipping off to the southward and finding the road again below where Gato stood.

Signing to Hazelton, Reade rose softly and started off. Two or three minutes later the young engineers were a hundred yards away from Gato, though in a rock-littered field where a single incautious step might betray them.

"Come on, now," whispered Tom. "Toward the mine."

"And run into Gato?" grimaced Harry. "Great!"

"If we meet him we ought to get away with him between us," Tom retorted. "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. Doesn't that look as though he wanted to sell? Harry, Don Luis has buyers in sight for his mine, and he'll sell it for a big profit provided he can impose on the buyers!"

"What does he want us for, then? He spoke of engineering problems."

"Don Luis's engineering problem," uttered Tom Reade, with deep scorn, "is simply to find two clean and honest engineers who'll sign a lying report and enable him to swindle some man or group of men out of a fortune."

"Then Don Luis is a swindler, and we'll throw up the job," returned Harry Hazelton, vehemently. "We'll quit."

"We won't help him swindle any one," Tom rejoined. "We won't quit just yet, but we'll stick just long enough to see whether we can't expose the scoundrel as he deserves! Harry, we'll have to be crafty, too. We must not let him see, too soon, that we are aware of his trickery."

CHAPTER VIII

DANGLING THE GOLDEN BAIT

Creeping closer to the mine, Tom and Harry saw the ore dumped from a train of forty mules. They also heard the fellow in charge of the train say that he would be back with two more loads that night.

"We don't need to wait to see the rest of the ore brought," Tom whispered to his chum. "We know enough now."

"Look over there," urged Hazelton. "There goes the rest of the trick. Men are shoveling the borrowed ore into the ore hoists."

"Of course," nodded Tom, disgustedly. "The ore is going below, to be piled in the tunnels. It will be 'salted' there all right for us to inspect in the morning. Oh, this trickery makes me sick!"

"What are you going to do now?" Hazelton asked.

"We may as well go back to the house and get some sleep."

"I'm strong for getting out of here in the morning," Harry muttered.

"Fine!" Tom agreed. "So am I. But what I want to do is to find out who is marked out for the victim of this gigantic swindle.

I want to put the victim wise. I'd be wild if I failed to find Don Luis's intended dupe and tell him just what he's in for."

"Do you imagine that Montez will ever allow us to get face to face with the man who's to be fleeced?"

"He won't do it intentionally, Harry. But we may have a way of locating the victim in time to save him from being robbed."

"Anyway, I should think the victim would have every chance in the world to sue and get his money back," Harry mused.

"How is one to get back the money that he has put into a gold mine?" Tom demanded. "Everyone knows that the most honest mine is a gamble. It may stop turning out paying ore at any hour.

Besides, what show would a stranger have in the courts in this part of Mexico? You have heard Don Luis boast that he practically owns the governor of Bonista. No, sir! The only way to stop a swindle will be to stop it before it takes place."

Tom rose from his hiding place, back in the dark away from the lights at the mine shaft. He nudged his chum, then started to creep away. Presently they rose and moved forward on foot. Ere long they had left the mine well behind.

"I hate to go back into that polished robber's house at all,"

Harry muttered. "Tom, what do you say? We can cover at least the first dozen miles between now and daylight. Let's make a streak for the railway and get back to the States."

"But what about saving the victim of the intended swindle?" objected Reade.

"We could come out with a newspaper exposure that would stop any American from buying the mine, or putting any money into it,"

proposed Hazelton.

"We might, only no newspaper would print such stuff. It would be libelous, and subject the newspaper editor to the risk of having to go to jail."

"All I know," sighed Harry, "is that I want, as speedily as possible, to put as much distance as possible between us and Don Luis's home."

"We'll go out through the front door, though, when we go," Tom proposed. "We won't sneak."

They did not encounter Gato on the way back to the big, white house. Though they did not know it, the boys were being trailed by the alert, barefooted Nicolas. Nor did that servant feel easy until he had seen them softly enter the house. Then Nicolas, as before, stretched himself on the floor before the door of the rooms occupied by the young engineers.

Tom's alarm clock woke him that morning. In another moment Reade was vigorously shaking Hazelton.