"God knows." Miller threw out his hands in a hopeless gesture. "I don't." "But there must be some motive for the crime," argued the chauffeur. "Miss Kathleen must have suspected something before taking ..." Powerful hands on his throat choked his utterance. "Never mention Miss Kathleen's name in that connection again," commanded Miller, his voice low and stern. "You hear me, you dog!" and he shook Heinrich until his teeth rattled, then released him. "Pardon," gasped the badly frightened man. "I meant no offense." "See that you follow my instructions hereafter." "Yes, sir"--Heinrich caressed his throat tenderly, and looked at Miller with a new respect. "I was only going to mention, sir, that Mr. Spencer meddled in what did not concern him. I believe he suspected what I have come to believe." "And what is that?" "That this photography business is only a blind." "A blind?" Miller looked thoughtfully at his companion. "Suppose you pull up a chair; wait, first hang your cap over the keyhole of the hall door." While waiting for Heinrich to follow his instructions Miller seated himself. "A blind?" he repeated. "No, no, Heinrich, you are mistaken; Mr. Whitney has invented a very perfect aeroplane camera, of that I am thoroughly convinced. And our country needs it...." "Undoubtedly, sir," Heinrich almost stuttered in his growing excitement. "But he has invented something that we need more...." "What is that?" "I don't know, sir." Miller, who had been leaning forward in his eagerness, drew back. "Don't waste my time, Heinrich," he said roughly. "Your time won't be wasted," protested the German. "Have patience and let me explain. I cannot manage this affair alone, I need assistance--and --you are a frequent caller at the Whitney house...." "Well, what then?" "Mr. Whitney may be persuaded to take you to his studio ..." the chauffeur hesitated. "Proceed," directed Miller shortly. "You can count on me." "Good," the chauffeur hitched his chair closer. "Day before yesterday I carried a telegram up to the studio. Not hearing any sound in the room, I carefully turned the knob of the door and found it unlocked. For months I have tried that door, hoping for just such luck," he interpolated. "Opening it very softly, I saw Mr. Whitney standing with his back to me, and facing the muzzle of a rifle. I had only time to note that the rifle was braced on two iron brackets and that Mr. Whitney was holding a string which was attached to the trigger; when I saw a flash, the rifle's recoil--and Mr. Whitney still standing just where he was." Miller stared incredulously at Heinrich, down whose face sweat was running; the man was obviously telling the truth--at least, what he believed to be the truth. "Wake up, Heinrich," he said skeptically, and the chauffeur flushed hotly. "It's God's truth I'm telling you," he declared solemnly. "For the sake of the Fatherland, believe me."