"But," perplexedly, "if I remember correctly, Rosa testified at the inquest that the servants' bedrooms are not in the attic but on the floor beneath." "They are, Herr Captain. On answering the bell from Mr. Whitney's studio I found Miss Grey there trying to revive him." "You answered the bell at four in the morning?" in surprise. "I understood you did not sleep at the Whitneys'." "Nor do I, Herr Captain; but last night I took Vincent's place and occupied his bedroom. When I reached the studio, I at first thought Mr. Whitney dead," continued the chauffeur, after a slight pause, "and rushed to summon a physician. On his arrival I assisted him to carry Mr. Whitney to his bedroom." "Did you see Miss Kathleen?" "Not after giving her the special delivery letter"--Henry's sidelong glance escaped Miller's attention--"when you were with her in the drawing-room; but I did hear her talking to Mrs. Whitney and the nurse in her father's bedroom just before I left the house to come here." "Keep me informed of what transpires at the Whitneys'," directed Miller, picking up his coat. "Very well, Herr Captain. Permit me to help you." The chauffeur stepped closer to his side and while assisting him, whispered: "Did you get the invention?" Miller thrust his right arm into the coat sleeve with slow precision, and his left arm into its sleeve with equal care before answering. "Yes." "God be praised!" Henry stepped back, his eyes snapping with delight. "Ah, we will win it yet, that Cross!" he exulted; then cautiously took from an inside pocket a folded sheet of letter paper and with care removed from between the pages a piece of paper. "When Miss Grey was occupied in her effort to revive Mr. Whitney I looked quickly about the studio," he explained. "This paper caught my eye--and I bring it to you, Herr Captain." "Thanks," laconically, laying the paper down on the desk. "One moment before you go," and from a well-filled wallet he extracted a treasury bill whose denomination caused Henry's eyes to beam with pleasure. "At service, Herr Captain," he said, saluting. "I will return and report later." "Very well, Henry," and the chauffeur bowed himself out, but on the other side of the door he hesitated, fingering Miller's tip with satisfaction. "He is liberal, that von Mueller," he muttered. "But it is just as well not to tell him that there were two sheets of finger prints," and he went whistling down the corridor. Tiptoeing to his door, Miller listened for a second, then, convinced that the chauffeur had moved away, he turned the key in the lock. Going to his desk, he picked up the sheet of finger prints and studied them long and attentively; then glanced down at his right hand. Horror lurked in the depths of his frank eyes. "The mark of Cain," he stammered, and opening the silver frame containing Kathleen Whitney's photograph, he deftly slipped the paper between the two pieces of cardboard. * * * * *