it?"

"Roadster. Looked like it could go."

Matt puzzled over this disquieting information all the way to Brigham's. They were held up about five minutes at the general store, buying a couple of two-quart canteens and having them filled with gasoline. When they left the Five Points and shot along Grand Avenue, each had a receptacle securely lashed to the head of his machine.

Thirty miles an hour was about the limit of Clip's motor-cycle. Clip had recently bought the machine of Ed Penny, and had equipped it with new tires, so that it was in a perfectly serviceable condition.

Twenty miles an hour for five hours would turn the trick. But that was too close figuring. The boys were a quarter of an hour late getting away. This time would have to be made up, and, besides that, Matt wanted to gain on the schedule so as to have a little leeway for possible accidents.

"How's the going between the Arizona Canal and Castle Creek Cañon, Clip?" queried Matt, as they whirled into the Black Cañon road.

"Fine to Frog Tanks," answered Clip. "From there to the cañon not so good. In the cañon it's mighty poor."

"Then we'll have to make all the time we can at this end of the route. Open 'er up, Clip!"

Both boys opened the throttles and let the reserve power shoot through the machinery. The needle of Matt's speedometer indicated thirty-two miles an hour.

"Great!" cried Matt, after giving Clip the figures. "That little one-cylinder is just naturally humping herself, Clip. We've got five hours for the trip, but at this pace we could almost do it in three."

"Hard trail in the cañon, Matt. There'll be plenty of lost time there. What's the game, anyway?"

Matt explained as they dashed along. The excitement of the work ahead brought a glow to Clip's eyes.

"Fine!" he exclaimed. "Motor Matt, the Governor's Courier! You'll get through on time even if I can't."

"Whether you're in at the finish or not, Clip, we split that hundred dollars right in two in the middle. If we ever get started for Denver, old chap, the money will help."

"But that red roadster!" scowled Clip. "How did those roughs get next to this work of yours?"

"That's too many for me," answered Matt.

"They must have suspected something. They were there, in front of the capitol, waiting. Mighty queer!"

Matt's lips compressed into a thin line and his eyes flashed.

"We'll have to keep a keen look-out for trouble," said he, "and dodge it, if any comes our way."

A few minutes later they were crossing the bridge over the Arizona Canal. Matt pulled out his old silver watch.

"Only sixteen minutes to one," he announced, with a note of exultation, "and we're fifteen miles on our way."

"Thirty miles to Frog Tanks and twenty to the next water," said Clip. "We ought to have brought a water-canteen, too. The heat is something fierce."

"We'll drink at the well, Clip, and pick up something to eat at the same place. We ought to be there in forty minutes, at the outside."

After they left the Black Cañon road, just beyond the bridge, Matt was in a country entirely new to him. The road was a bit cut up and sandy in places, but Clip whaled his machine along and they did a trifle better than thirty miles.

Two or three roads entered the one they were following, and they were all as well traveled. Here Matt's wisdom in bringing Clip along, even at the loss of some speed on the Comet's part, was made manifest. But for Clip, Matt might have gone astray on the wrong trail.

The boys were now in the region of big sahuara cacti, and the great trunks flashed past them as telephone-poles recede behind a rushing train.

In the dusty places of the road the broad tracks left by the tires of an automobile could be plainly seen. The red roadster was ahead of them. Matt studied the skyline in advance, wondering how far away the two ruffians were and what their designs could be. He saw nothing of the red car, and presently the square walls and flat roof of an adobe house broke on his vision.

Behind the house was a primitive stable, thatched with grass, and a small corral constructed of ocotilla poles braided together with wire. Between the house and stable was an iron pump and a watering-trough.

"That's the ranch where we get our water," remarked Clip. "Two bits apiece for a drink. There's Gregory, the rancher, out in front."

Gregory, the rancher, got up in surprise as the boys came to a stop at the pump. He stared at the machines.

"Waal, I'll be hanged!" he muttered. "They've got them hossless wagons on four wheels an' two wheels. Reckon they'll be havin' 'em on one wheel next. Dry? Help yerself. Two bits apiece fer all ye kin swaller. Water costs money in the desert."

Leaning their machines against the water-trough, the boys began working the pump.

"Did you see a horseless wagon on four wheels go past here, Mr. Gregory?" asked Matt.

"Sure. Two fellers was on the seat. They stopped fer water an' then hiked right on, jest as though they was in a hurry ter git some'r's. Friends o' your'n?"

"No, we don't know them," answered Matt. "How long since they passed?"

"Less'n five minutes."

"Got anything to eat in your place?" went on Matt. "We can't stop more than a minute or two."

"Sho!" exclaimed the man. "Ever'body 'pears ter be in a hurry this arternoon. I got jerked beef, crackers, an' all kinds o' canned goods, say nothin' erbout——"

"'Jerked' and crackers'll do," interrupted Clip. "We'll go in, Gregory. Get us a hand-out we can tote in our pockets."

"Sartain," answered Gregory.

The boys were not in the adobe house to exceed five minutes, and they wouldn't have been there to exceed three if Gregory had been a little more spry in his movements. Stuffing their crackers and dried beef into their pockets, they ran out of the house and to their machines. Scarcely taking time to look the motor-cycles over, they pulled them upright and got into the saddles.

Matt pedaled away, twisting on the gasoline and the spark. But the motor did not work—he was still pushing the machine ahead with the pedals. He halted to investigate and find out what was wrong, and at that moment a startled cry came from Clip.

Matt looked around. Clip was having the same trouble getting his motor-cycle started. But Clip had made another discovery which sent a shock of consternation through both him and Matt.

"Our gasoline-cans!" cried Clip. "Where are they?"

Then, for the first time, Matt saw that his reserve supply of gasoline had been removed from the head of the Comet. Clip's can had disappeared in the same mysterious manner. With a sudden, paralyzing thought, Matt examined the tank back of his saddle.

The tank was empty!

Doubling up his fists, Clip jumped for Gregory. The latter sprang back and stared at Clip in astonishment.

"You know who did it!" shouted Clip menacingly. "The men on that red roadster hired you to stop us! You had some one hiding here. While we were in the house the gasoline was taken away. We'll give you a minute to get it back. Sixty seconds, Gregory!"

The rancher continued to stare.

"I don't know nothin' about what you're gittin' at," he muttered blankly. "I ain't makin' trouble fer no one, an' them other fellers didn't hire me ter do a thing. Keep away, I tell ye! Thar's two o' you, but I'll give ye a hot time if ye git too hostile!"

Gregory picked up an ax as he stepped back, and then stood confronting the boys threateningly.