"If I explain that the experiment wouldn't be possible," said Leighton with a laugh. "The thought must come through unconscious suggestion, or our Ghost of the Forgotten will refuse to appear. In a way, it is like a game--and is more interesting than most games. Did you ever play the game of twenty questions?" "I have," interjected Una. "It's this way. Something--a book, a piece of furniture, anything at all--is chosen by one set of players to be guessed by the other set. Then the set who know the secret have to answer twenty questions about it, asked by the other side. The questions sound silly, but they usually discover the secret." "Is your experiment like Una's game?" asked David. "Not exactly. Sit down in this chair and you'll see." Seated as directed, the psychometer stood a little back and at one side of him. "Now," said Leighton, giving him the electrodes, "hold these, one in each hand." "It's like an electrocution!" exclaimed Una. "Are you very uncomfortable?" "Oh, quite the contrary! Now, Mr. Leighton----" "Ready? Here goes the current. You will scarcely feel it." Leighton pulled out a small lever. A faint humming sound was heard. The electric finger on the mirror in the machine became suddenly illuminated. "Do you feel it?" asked Una. "Yes; it's rather nice. This hero business is all right, especially when you preside at the performance, Una." "Now for your game of twenty questions, Uncle Harold. Of course, you are going to let me into the secret?" "How can I?" he retorted. "David has the secret." "I have it?" repeated the other, perplexed. "Certainly. But this isn't exactly a game. You'll find it tedious, Una. Why not stay with Mrs. Quayle in the library until it's over?" "Nonsense! Of course I'll stay here," she replied firmly. "What am I to do?" asked David. "Holding these handles is easy enough--but nothing happens." "Let me explain," said Leighton. "I am going to give you, one at a time, a number of disconnected words. As you hear each word, you must reply with the first word that suggests itself to your mind. For instance, suppose I say 'black.' The word gives rise, instantly, to some answering mental picture, and that picture will suggest a word with which your experience has associated it. Thus, when I say 'black,' you may think of 'night'; or, if your thought goes by contraries, the word 'white' may occur to you. In any case, tell me the first word that comes into your mind upon hearing my word--and remember that the promptness of your reply is an important factor in the experiment." "It sounds easy," remarked David. "Let's begin." On a small table at which he was standing, Leighton placed his watch, a writing-pad and pencil. Seating himself, he commenced the experiment in the way he had proposed, noting each word as he gave it on the pad before him, and marking the number of seconds elapsing before each of David's answers. Una, ensconced in a large armchair, watched the scene intently.