Here a Mexican boy was on duty. When the visitors entered, his hand was resting on the telescope. A bright red sash around his waist imparted a touch of picturesqueness to his costume. He was perhaps only twelve or thirteen years of age, but wonderfully keen and alert-looking for his years. At a glance from his master, the youngster took his departure, closing the door behind him. “Gentlemen,” remarked Mr. Robles, when they were again alone, “perhaps before I brought you here I should have exacted the promise I am now going to ask you to make. Grace and Merle know that I am a recluse and wish to live undisturbed by curiosity-mongers or tittle-tattlers. I want nobody but the friends I deliberately choose to know about my habits of living or the contents of my home. Only in this way can I hope to be left alone. Therefore, please give me your word, Mr. Willoughby and Lieutenant Munson, that you will not speak with any outsider about the things I am showing you today.” The promise was instantly given and sealed by a hearty hand clasp. “Now,” resumed the host in lighter tone, “perhaps you would like to view the landscape. I may explain that I had this observatory, as I call it, specially built and equipped so that I could sweep the valley from end to end. For example, I saw you two young men riding along the road this morning,” he went on, with a smile. “I saw one of you alight, about twelve miles from here—it was you, lieutenant—and tighten the girths of your saddle.” “Great Scott!” murmured Munson, in half-incredulous surprise. “Test the glass for yourself,” continued Robles, as, placing one eye at the lens, he adjusted the instrument. “Look”—and he stepped back, motioning Munson to approach. Munson peeped through the long tube and there came from his lips a cry of mingled delight and amazement. “Dick, Dick, there’s the store as large as life—Buck Ashley standing at the door and lighting a cigar. Geewhizz, and it must be twenty miles away.” He rose erect and made room for Dick. The latter gazed in silence for a few moments. When he turned to Mr. Robles he said: “It’s really wonderful—it is the most wonderful glass I ever looked through.” There was the glimmer of an exultant smile on the face of Ricardo Robles. “I saw you at the round-up across the valley the other day,” he remarked. “You were much nearer to me than is the store. And while I do not invite any confidence, Mr. Willoughby, you certainly engaged in a very spirited conversation, to say the least, with young Marshall Thurston. Indeed, I half expected to see you come to blows.” “What was that?” asked Merle in some trepidation. Willoughby had reddened. “Nothing of consequence,” he responded, almost curtly. “I had to tell the young cub to mind his own business. That was all.” “You certainly have the whole valley under observation,” remarked Munson, considerately diverting the conversation.