This image is an original version of magic dealer Jack Hughes' 'Ball in Glass' or 'Pentra-Spheres' trick. Designed in 1937, it was later also called 'Hole in One.' A modern version, still available today, is known as the '19th Hole.'
Jasper Maskelyne received one of the first of these tricks to be made, as the note by Jack Hughes shows. The Great Levante and Arthur Dowler, another magician, also got one of the initial batch.
Effect: Six different coloured balls are placed on a tray with an inverted glass in the centre. The balls and glass are covered with a cloth. A spectator names a colour. When the cloth is removed the ball matching that colour is beneath the glass.
The working action is remarkable and mechanically perfect. Easy to do, yet a confounding trick.