Charles Wheatstone (1802-1875) invented this apparatus to demonstrate various forms of wave motion. The first machine was made by John Newman, 122 Regent Street, London around 1850. Later versions carry various inscriptions and Elliott Bros. named on our machine were probably distributors. The machine contains two wooden strips called sliders each with a wave profile cut on its top edge. These strips slide horizontally parallel to one another. Across them lie a series of horizontal bars with white beads on their ends. As the sliders move these beads move up and down forming wave patterns on the sides of the machine. At the centre of each bar another rod projects vertically from the top of the machine with another white bead on it. A further pair of sliders fit horizontally below the bars and cause the bars to move transversely in the horizontal plane. By appropriately combining these motions the white beads can be made to produce plane and circularly polarised waves. But the machine is more complex because a stationary wave pattern is already built in to the bar and bead assembly, and moving the sliders produces combinations of the travelling wave with the in-built wave. This produces spectacular effects and demonstrates deep understanding of wave motion. In our case we have only two of the original set of perhaps 16 sliders, and three further sliders have had to be made to make the machine operative.

Inscriptions / Translations:  Wheatstone Inv.
Elliott Bros London 31

Notes:  https://www.youtube.com/watch?v=bw4R5qXaIww