The magician takes a hat and places a glass of milk in it. The magician then shows an empty nickel plated tube, takes the glass out of the hat and places the tube over the glass. On turning the tube upside down the audience expect the milk to pour out, but the tube is shown to be empty. The glass has vanished, only to be found back in the hat. To protect the secret, the photograph does not include all the apparatus for this effect.
German magician Steffen Taut has kindly supplied some information on the development of this trick. He says that in late 1930 or early 1931 the German Friedrich Ickas had the idea to use the special glass with real milk. This made for a very strong illusion. Ickas asked the Dresden manufacturer Manfredo to build such a prop for him. It was finally delivered to Ickas on March 15th, 1931, by Manfredo. Manfredo immediately marketed the trick as “Milchglastrick” and became famous for this trick. His version was larger than the props of his (later) competitors, and thus better suited for stage work. The size of a typical Manfredo tube is 210mm (height) by 80mm (diameter). Davenports did buy tricks from Manfredo and it is likely that Manfredo was the supplier of the Milkos sold by Davenports.