Houdini's Radio Illusion
As Houdini's career moved into the radio age, he incorporated this new technology into his act. To perform the radio illusion, Houdini would begin by displaying an over-sized version of a radio cabinet, roughly 6 feet wide and proportionally high and deep, equipped with over-sized dials. The cabinet stood on high legs, skirted with a black cloth. Houdini would raise the cloth to show the audience that nothing was amiss. He then had assistants lower the front and back of the over-sized radio, showing there to be nothing inside, except a few wires and tubes, mimicking the actual inside of a radio. He would then turn the dials of the radio, causing music to emanate from the giant radio. Suddenly, the cabinet would open and a girl would appear from within.
The secret to this trick was the table itself, which contained what magicians call a "bellows top" consisting of two thin slabs, with several inches of cloth folded in between the edges, so the lower top can be set down a specific distance. In this case, it was let down less than the depth of the cloth that skirted the table. The girl was initially hidden inside the cabinet, as Houdini demonstrated that nothing was beneath the cloth. As he moved on to demonstrate the inside of the radio cabinet, the girl would simply lower herself through a trap door, into the bottom area, where she remained hidden due to the cloth at the bottom. As the radio cabinet was once again closed and the music began, the girl would come back into the cabinet through the same trap door where she would make her "magical" appearance.