ENVELOPE TRICK.
A person is requested to write a question with ink upon a card. The card is now placed in an envelope and sealed. The performer takes the envelope from the room for a few seconds. On coming back he returns the envelope to its owner and also another envelope, which on being opened will be found to contain a card, on which is written an answer to his question. The envelope, however, in which his question is sealed shows no evidence of having been tampered with in the slightest.
When the performer leaves the room he immediately takes a sponge which is saturated with alcohol and rubs it over the surface of the envelope, which makes it transparent, and he is thus able to read what is written on the card inside. He then writes a suitable answer on another card, which he seals in another envelope. The alcohol evaporating very quickly there is no sign of it upon the envelope when returned to its owner.
The End.