human
This machine, my 'ghost-hunter,' solves the problem. A Russian scientist discovered that an electric current passing through the body is affected by any abnormal physical, or nervous, activity there encountered. Thought is a form of electric impulse and would, therefore, modify any other electric force crossing its path. Hence, Tarchanoff's law. Its practical application means, the literal measurement of our mental ripples. And this is done by the psychometer.
gpt
How?
human
It's very simple. You hold these electrodes in your hands. An electric current is turned on and passes through you. While you are thus charged with electricity, I throw the stone, the thought, into your mind. The degree, or quality, of disturbance caused by this thought modifies the electric current, the varying agitation of which is made visible by the movements of an electric finger across this mirror. From there it is recorded on the sheet of paper in this cylinder.
gpt
What a horrible contrivance!
human
I see how it works, mused David,
gpt
If I explain that the experiment wouldn't be possible, said Leighton with a laugh.
human
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?
gpt
I have, interjected Una.
human
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.
gpt
Is your experiment like Una's game?
human
Not exactly. Sit down in this chair and you'll see.
gpt
Now, said Leighton, giving him the electrodes,
human
It's like an electrocution! exclaimed Una.
gpt
Are you very uncomfortable?
human
Oh, quite the contrary! Now, Mr. Leighton----
gpt
Ready? Here goes the current. You will scarcely feel it.
human
Do you feel it?
gpt
Yes; it's rather nice. This hero business is all right, especially when you preside at the performance, Una.
human
Now for your game of twenty questions, Uncle Harold. Of course, you are going to let me into the secret?
gpt
How can I? he retorted.
human
David has the secret.
gpt
I have it?
human
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?
gpt
Nonsense! Of course I'll stay here,
human
What am I to do? asked David.
gpt
Holding these handles is easy enough--but nothing happens.
human
Let me explain, said Leighton.
gpt
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.
human
It sounds easy, remarked David.
gpt
Let's begin.