A DISAGREEABLE SURPRISE.

Penny's motor-cycle was a one-cylinder machine, and not a very late model. It weighed as much as the Comet, which had two cylinders and twice as much horse-power. Matt's machine, however, was the very last word in motor-cycle construction. In a pinch, it could streak along at sixty-five miles an hour, or, on the low gear, would do five just as readily. It was somewhere between these two extremes that Matt had to travel in order to let Chub keep alongside, but at no time were they doing less than a mile every two minutes.

A highway known as the Black CaÑon road led to the Bluebell Mine, and by taking a cross-thoroughfare shortly after leaving the house the boys whirled into their direct course. It was about eleven o'clock when they started, and they were planning to make their first halt with Delray at the Bluebell.

"You could double the pace, Matt, if it wasn't for me," said Chub, leaning over the handle-bars and opening his machine up for all it would stand. "This thing-a-ma-jig of Penny's ain't in the same class with yours."

"Oh, well, it's not so bad for a back number," answered Matt. "We're doing our thirty miles an hour just now, and I guess that's plenty. We'll make the Bluebell easily by noon," he added, cocking his eye at the sun.

"I hope nothing has gone wrong with dad since he wrote that letter," went on Chub, after a brief silence. "He's able to take care of himself, so far as Bill Jacks is concerned, but if Hawley sends any roughs out there, something is sure goin' to happen."

"I don't believe in crossing any bridges before you get to them, Chub. We'll just push hard for the place where your father made his strike, and hope for the best."

It was half an hour after they left Phoenix when they crossed a new plank bridge over the Arizona canal, fifteen miles out.

"They weren't long getting another bridge over the canal," observed Chub, as the machines left the planks and started up a gentle slope beyond. "That was one bridge, Matt, you came pretty near not crossing, even when you got to it."

Chub referred to the time Motor Matt was racing for Phoenix to take his place in the bicycle contest. A hireling of Hawley's had blown up the bridge in front of the Comet, and Matt had been obliged to cross the chasm on a narrow stringer.

From the canal it was only five miles to the Bluebell Mine, and the distance was rapidly covered. As the boys drew close to the derrick, the ore-dump, and the little house where the watchman usually kept himself, they slowed down their machines and looked around expectantly. There was no sign of life about the place.

"Probably Del's in the shack, gettin' his dinner," hazarded Chub. "I guess we could take time to eat a little something ourselves before we go on to the 'strike,' eh, Matt?"

"Del's not getting dinner, Chub," answered Matt, coming to a halt and slipping out of his saddle. "There's no smoke coming out of the chimney, and that means there's no fire in the stove. I'll bet a picayune against a last year's bird's nest that Delray isn't here."

"Hang it all!" returned Chub, leaning his machine against the wall of the house, "he's the watchman, an' he's got to be here. We'll investigate."

They went into the house. The door had not been locked, but there was no sign of the watchman in the cabin's single room.

"He can't be far away," averred Chub, "or he wouldn't have left the door like that."

"Whether Delray's here or not, Chub, that doesn't cut much of a figure with our work," said Matt. "We know where we want to go and how to get there."

"Sure, but I'd like to see Del and ask him if dad has tried to shoot anything into Phoenix by wireless. We can lose a little time here, I guess, without spoilin' the big end of our game."

An exclamation from Matt drew Chub's instant attention.

"Great Scott, Chub, look there!"

Matt was pointing toward the table which supported the Bluebell end of the wireless apparatus. Sending and receiving-instruments had been completely wrecked, and parts of them were scattered over the floor.

"Well, what d'you think of that!" muttered Chub. "Hawley was bound dad wouldn't get any message through to me by way of the Hertzian waves. Wonder if Dace Perry did this, too?"

"Not much, Chub. These instruments, like those at your house, must have been broken some time to-day—you see, Del hasn't even had time to pick up the scrap. If Perry smashed the apparatus at the Phoenix end of the line, he'd have to be chain-lightning to get here and wreck these instruments, too. No, it wasn't Perry."

"Think it was Jacks?"

"One guess is as good as another. I'd like to hear what Del has to say about this. Maybe he's down in the mine?"

"We'll take a look," said Chub, starting for the door.

The ore-dump and derrick were only a little way from the house, and the boys were soon climbing the dump to the platform at the mouth of the shaft. Kneeling down at the opening in the platform, they leaned over and shouted Delray's name into the pitchy darkness below. No answer was returned.

"He couldn't hear us if he was in some of the levels or crosscuts," remarked Chub. "Del was hired to keep a sharp watch on this mine while it's lying idle, an' I don't think he'd go 'way. He must be down there. I'll go back to the house for a candle, and we'll take a hunt through the workings."

Chub was but a minute in getting back with a couple of candles. These were lighted, and the boys started down the rickety ladders, Matt leading the way.

The shaft was a hundred feet deep, and there were two levels opening off it—one half-way down, and the other at the bottom.

Matt and Chub got off the ladders at the first level, walked to the end of the passage, and there, by means of a winze connecting the two levels, descended to the bottom of the mine and made their way back to the shaft again. Thus they made the complete circuit of the workings—and without finding any trace of Delray. They climbed disappointedly up the shaft, after having been in the mine for about half an hour.

"This is tough luck, Matt," muttered Chub. "I wonder if there has been any foul play here? When Hawley is out for a big winning, it isn't much that he'll stop at."

"He wouldn't have the nerve to go too far with Delray," answered Chub. "Hawley is unscrupulous, all right, but he's not going to get the law down on him if he can help it."

"He might have had some of his roughs run Delray off while those wireless instruments were bein' smashed."

"No, I don't think he'd do even that. It looks to me as though some villain had stolen into the house and wrecked the instruments while Del was out—just as the job was done at your place in Phoenix."

"The farther we go in this thing the more mysterious it gets."

"And the more we see that Hawley is leaving no stone unturned to beat your father out of that mining-claim. We'd better make a quick run to the 'strike,' Chub, and see what shape matters are in there. From the looks of things this far, the prospect worries me."

"I'm some worried myself," admitted Chub, "and I'm gloomed up a heap because we can't find Delray. I know where that pack-trail is, though, and we'll hit it good and hard."

While they were talking they were stumbling down the ore-dump and making their way to the place where they had left their motor-cycles.

"There's a lot of shady characters in these parts," Chub went on, "who wouldn't pass up a ten-dollar bill if Dirk Hawley wanted any crooked work done. Hawley's friends are mainly among that class."

"Bad as he is, though," said Matt, "there are some good things about the gambler. They say he has a daughter in school in 'Frisco, and that he keeps her there so that neither she nor her friends will find out what sort of a man he is."

"That's Edith Hawley you're talkin' about, Matt. I've heard the same yarn, but if Hawley's keeping the girl in 'Frisco an' tryin' to make her and her friends think he's a saint, he's going to get fooled. The girl's here on a visit, and if she's as bright as they say, she'll find out that——"

The words died on Chub's lips. He and Matt had rounded the corner of the house, and had come to a halt facing the spot where they had left their machines.

The motor-cycles were not there!

"Stung!" gasped Chub, staring at his chum in consternation. "Am I in a trance? Didn't we leave our machines here, Matt?"

"We did," answered Matt excitedly, "and they're gone."

"Somebody must have come here an' rode 'em off while we were in the mine!" cried Chub. "More of Hawley's work, and I'll bet my hat on it. He's got us now. That's the one thing he could do that would knock us out entirely. Oh, what a pair of dubs we were!"

Chub, in despair, dropped over against the side of the house and banged at the adobe wall with his clenched fists. Matt, after a moment's thought, darted away toward the road.

"Where you goin', Matt?" cried Chub.

"To see which way the thieves went," called back Motor Matt.

"What's the use? Think we could overhaul 'em on foot? This is where Johnny Hardluck puts us down and out, an' no mistake!"

Chub, terribly cast down, continued to lean against the house and say things to himself. He watched Matt absently as he ran up and down the road, reading the signs left in the dust.

Suddenly Matt halted, turned sharply about, and called to Chub.

"We've got a fighting chance!" he yelled, peeling off his coat and casting it by the roadside. "Strip, Chub, and unlimber those short legs of yours. There's a good hard run ahead of us."

The bewildered Chub got out of his coat and dropped it where he stood, then he started in Motor Matt's direction, wandering what was in the wind. How were the two of them, on foot, ever going to catch up with the motor-cycles?