Place a glass of any liquid upon the table, put a hat over it, and say:
“I will engage to drink the liquid under that hat, and yet I’ll not
touch the hat.” You then get under the table, and after giving three
knocks, you make a noise with your mouth as if you were swallowing the
liquid. Then getting from under the table, you say: “Now, gentlemen, be
pleased to look.” Some one, eager to see if you have drunk the liquid,
will raise up the hat, when you instantly take the glass, and drink the
contents, saying: “Gentlemen, I have fulfilled my promise. You are all
witnesses that _I_ did not touch the hat.”