"Theater," was Leighton's first word. "Music," came the prompt reply. "Noise." "Sleep." "Lion." "Teeth." "Sound." "Desert." "Ocean." "Blue." A long series of similar question and answer-words followed, apparently chosen at random and not indicating any sequence of ideas. Leighton spoke with exaggerated monotony, his eyes fixed on David, his hand moving with mechanical precision as he jotted down the words and the time taken for each reply. Scarcely any agitation was noticeable in the finger of light upon the mirror, and this part of the experiment seemed--at least to Una--a failure. "I don't see what the machine has to do with it," she said, somewhat puzzled. "David could just as well answer your words without holding those things in his hands." "Una," said Leighton, giving this as the next question-word and ignoring the interruption. David smiled, hesitated a moment before replying, while the electric finger trembled slightly and then moved, slowly and evenly, back and forth across the mirror. "Light," he answered softly. More question-words followed, most of them receiving prompt answers and producing no appreciable effect in the psychometer. It was noticeable, however, that words having to do with places gave a different result--a vibration of the electric finger, indicating, according to the theory, that they awakened a deeper interest than other words in David's mind. In experiments of this kind the operator's choice of words is carefully made, as a rule, and not left to chance. They usually have a certain continuity of meaning. Theoretically, also, the operator's personality is kept in the background, so that the subject is freed from any emotional impulse save that created in him by the question-words. But there is always the possibility that this personality will unconsciously influence the subject's mind, which is thus impelled in directions it might not otherwise take. Hypnotism may thus, unintentionally, play a part in an experiment of this kind, and the subject made to follow, in the words uttered and the degree of emotion displayed, his inquisitor's suggestions. It would be hard to tell whether hypnotism gradually came into Leighton's experiment with David. Certain it is that as the trial went on a change came over the two men. Their features grew tense, they were as vigilant to thrust and parry in this game of words as two fencers fighting on a wager whose loss would mean much to either of them. In David anxiety was more marked. The electric finger in the psychometer, unconsciously controlled by him, moved more rapidly and with greater irregularity over the face of the mirror. At times it remained fixed in one place; then, with Leighton's utterance of some new word, it would leap spasmodically forward, in a jagged line of light which would be recorded automatically on the cylinder at the back of the machine.