As before, you ask a gentleman in the company to write down a number on a piece of paper, and a lady to write down another number. These numbers they show to the other guests. You then inform the company that you will ask any one of them three questions, and by the way they are answered you will guess what the product of the two numbers is. (For instance, if the numbers were 13 and 17, then 13 multiplied by 17 is--let's see, thirteen sevens are--thirteen sevens--seven threes are twenty-one, seven times one is--well, look here, let's suppose the numbers are 10 and 17. Then the product is 170, and 170 is the number you have got to guess.) Well, the company selects a lady to answer your questions, and the first thing you ask her is: "When was Magna Charta signed?" Probably she says that she doesn't know. Then you say, "What is the capital of Persia?" She answers Timbuctoo, or Omar Khayyam, according to how well informed she is. Then comes your last question: "What makes lightning?" She is practically certain to say, "Oh, the thunder." Then you tell her that the two numbers multiplied together come to 170. How is this remarkable trick performed? It is quite simple. The two people whom you asked to think of the numbers are confederates, and you arranged with them beforehand that they should write down 10 and 17. Of course it would be a much better trick if they weren't confederates; but in that case I don't quite know how you would do it. I shall end up this interesting and instructive article with a rather more difficult illusion. For the tricks I have already explained it was sufficient that the amateur prestidigitator (I shall only say this once more) should know how it was done; for my last trick he will also require a certain aptitude for legerdemain in order to do it. But a week's quiet practice at home will give him all the skill that is necessary. THE MYSTERIOUS PUDDING