Here is an absolutely new method of performing the same trick
blindfolded, but with the aid of a confederate. You tell your friends
that by placing your hands on a person's head you can see with his eyes.
To illustrate this, tell your assistant to seat himself at a table, and
you then stand behind him blindfolded, with your fingers lightly
touching his temples. The cards are spread out faces down on the table,
and no matter which card he picks up and looks at, you at once say what
it is. Of course, you take the tip from him; but how? I will tell you.
He must keep his mouth shut and his teeth together. The slightest
pressure between his upper and lower teeth--so slight that it is quite
imperceptible--will cause his temples to throb--try it on your own
temples--and, of course, by the arrangement of a very simple code he can
communicate to you the name of each card. Say one throb stands for
hearts, two for diamonds, three for clubs, and four for spades. We will
say his temples throb twice. You say, "You are looking at a diamond."
Then we will suppose they next throb five times. You say, "It is the
five of diamonds," and so on. When you come to an ace, of course one
throb will suffice; when he picks up a knave, let him give two throbs in
rapid succession--a kind of postman's knock; a queen, a postman's knock
and one throb over; and for a king, a double postman's knock--rat-tat,
rat-tat. With a little practice and a more elaborate code, you can
describe all kinds of articles which may be selected--keys, watches,
books, etc. It is a capital trick and one which no one can possibly
discover.