deep into the wave.  Here, shaded by the broad-brimmed hats of white felt, such as the Arizona trooper of the old days generally affected, a match or two was struck and the neighborhood searched for “sign.”  The rocks around the tank were dry, the little drifts of sand blown down from the overhanging height were smooth.  Whatsoever splashing had been done by the horses of the outlaws there had been abundant time for it to evaporate, therefore the command could not thus far have gained very rapidly on the pursued.  But Drummond felt no discouragement.  Up to this point the way had been smooth and sufficiently hard to make wheeling an easy matter.  The wagons had been lugged along at brisk trot, the attending cavaliers riding at lively lope.  Now, however, there would be no likelihood of their making such time.  The ambulance could only go at slow walk the rest of the way, and the guards must remain alongside to protect the stolen funds, not so much from envious outsiders as from one another.  Pasqual Morales showed his accustomed shrewdness when he forbade that any one should try to burst into the safe and extract the money, for well he knew that if divided among the men there would be no longer a loadstone to hold them together, to call for their fiercest fighting powers if assailed.  The instant the money was scattered the gang would follow suit, and he be left to meet the cavalry single-handed.

The horses of the little detachment were not long in slaking their thirst.  The noiseless signal to mount was given, and, following in the lead of their young lieutenant, the troopers rode silently down the winding canon, Drummond and Sergeant Lee bending low over their chargers’ necks to see that they did not miss the hoof-prints.  Little by little the light of dawn began to penetrate the dark depths in which they were scouting, and trailing became an easier matter.  Presently the sergeant pointed to the face of the opposite slope, now visible from base to summit where an abrupt bend threw it against the eastern light.

“Yonder’s where the ambulance came down, sir.”

“I see, and we can’t be far from where it crossed.  Trot ahead and take a look.  Let Patterson go with you.  If you find a chance for short-cuts, signal.”

Another half-hour passed away and still the trail led along this strange, rock-ribbed groove in the desert, the dry bed of some long-lost stream.  When first met it seemed to be cutting directly across their line of march, now it had turned southward, and, for several miles ahead, south or west of south was its general course.  The light was now broad and clear, though the sun had not yet peeped across the mountain range to their left.  The pace was rapid, Drummond frequently urging his men to the trot or canter.  Out to the front four or five hundred yards, often lost to view in the windings of the way, Sergeant Lee with a single trooper rode in the advance, but not once had he signalled a discovery worth recording.