And Marianne, for the first time truly appreciating how great was the danger from which the mares had been saved, sighed as she looked them over again, one by one.  It had been a double triumph, this night’s work.  Not only were the mares retaken, but they had proved their speed and staying powers conclusively in the long run over the desert.  Hervey himself began hinting, as they rode on, that he would like “to clap a saddle on that Lady Mary hoss, one of these days.”  In truth, her purchase was vindicated completely and Marianne fell into a happy dream of a ranch stocked with saddle horses all drawn from the blood of these neat-footed mares.  With such horses to offer, she could pick and cull among the best “punchers” in the West.

Into the dream, appropriately enough, ran the neigh of a horse, long drawn and shrill of pitch, interrupted by a sudden burst of deep-throated curses from the riders.  The six mares had come to a halt with their beautiful heads raised to listen, and on a far-off hill, Mary saw the signaler—­a chestnut horse gleaming red in the morning light.

“It’s him!” shouted Hervey.  “The nervy devil has come back to give us a look.  Shorty, take a crack at him!”

For that matter, every man in the party was whipping his rifle out of its holster as Mary raised her field glass hurriedly to study the stranger.  She focused on him clearly at once and it was a startling thing to see the distant figure shoot suddenly close to her, distinct in every detail, and every detail an item of perfect beauty.  She gasped her admiration and astonishment; mustang he might be, but the short line of the back above and the long line below, the deep set of the shoulders, the length of neck, the Arab perfection of head, would have allowed him to pass unquestioned muster among a group of thoroughbreds, and a picked group at that.  He turned, at that instant, and galloped a short distance along the crest, neighing again, and then paused like an expectant dog, with one forefoot raised, a white-stockinged forefoot.  Marianne gripped the glass hard and then dropped it.  By the liquid smoothness of that gallop, by the white-stockinged forefoot, by something about his head, and above all by what she knew of his cunning, she had recognized Alcatraz.  And where, in the first glimpse, she had been about to warn the men not to shoot this peerless beauty, she now dropped the glass with the memory of the trampling of Manuel Cordova rushing back across her mind.

“It’s Alcatraz!” she cried.  “It’s that chestnut I told you of at Glosterville, Mr. Hervey.  Oh, shoot and shoot to kill.  He’s a murderer—­ not a horse!”

That injunction was not needed.  The rifle spoke from the shoulder of Shorty, but the stallion neither fell nor fled, and his challenging neigh rang faintly down to them.

“Mind the mares!” shrilled Marianne suddenly.  “They’re starting for him!!”