Vanishing Glass

Magician shows a drinking glass and a metal tube to his audience. The metal tube is placed over the glass. Half of the glass is seen protruding above the top of the tube. Magi now covers the whole thing with a silk or foulard. He smashes his hand down on the top and removes the silk. The glass has vanished! The tube and silk are shown to be empty. The glass can now be produced from somewhere else, such as a top hat, paper bag, etc.