“I want you four fellows to stick close to me now,” said Drummond, turning in saddle and indicating the desired set with a single gesture.  “We move straight for the leading wagon.  See that you don’t fire into it or near it.”

And these were the last instructions as they reached the ridge, and a hoarse murmur flew along the eager rank, a murmur that, but for Drummond’s raised and restraining hand and Sergeant Lee’s prompt “Steady there; silence!” might have burst into a cheer.  And then the leader shook loose his rein, and just touching “Chester’s” glossy, flank with the spur, bounded forward at the lope.

Out on the sandy barren, winding among the cactus plants, the weary mule-teams with drooping heads were tugging at the traces.  Bearded men, some still with coal-blackened faces, rode drowsily alongside the creaking wagons.  In one of these, the foremost, an arm in blue flannel suddenly thrust aside the hanging canvas curtain, and a dark, swarthy face, grooved from ear-tip to jaw with a jagged scar, appeared at the narrow opening.

“How much farther have we got to go, Domingo?”

“Only across this stretch, two—­three miles, perhaps.”

“Well, I want to know exactly.  The sun is getting blazing hot and these girls can’t hold out longer.  Tell Pasqual I say there is more danger of his killing them with exhaustion than there is of their making way with themselves.  Say the little one’s about dead now.  Here, take this canteen and get some fresher water out of the barrel under the wagon.”

The fellow hailed as Domingo leaned to the right, took the canteen-strap, and then reined in his foaming broncho.

“Hold your team one minute, Jake,” was the order to the driver, and, nothing loath, the mules stopped short in their tracks.  Pasqual’s ambulance was a few rods behind, and, to save time, Domingo dismounted and, placing the canteen under the spigot, drew it full of water, rewarded himself with a long pull, handed it up to the waiting hand above, and swung again in the saddle just as the second ambulance closing on the first came also to a willing halt, and the lead mules of the buck-board, whereon lay two wounded bandits, attended by Moreno’s womenfolk, bumped their noses against the projecting boot.

“Some cool water, for God’s sake!” gasped one of the prostrate men, and a comrade rode to the leading wagon to beg a little from Harvey’s well-filled barrel.  One or two men threw themselves from the saddle to the sands for brief rest.  The dust-cloud slowly settled earthwards in their wake.  Mules, horses, and men blinked sleepily, wearily.  There hung in the heavy air a dull, low rumble as of thunder in the far-off mountains.  There seemed a faint quiver and tremor of the soil.  Was there distant earthquake?

Suddenly a wild yell, a scream from Moreno’s buck-board, a half-stifled shriek from the white-covered wagon.  The man in blue leaped forth and made a mad dash for the nearest riderless horse.  Whips cracked and bit and stung.  The maddened mules flew at their collars and tore away, the wagons bounding after them, and Pasqual Morales, thrusting forth his head to learn the cause of all the panic, grabbed the revolver at his belt with one fierce curse.