Kaleidoscope, c 1817.
© National Media Museum / Science & Society Picture Library
The Kaleidoscope was invented by the scientist Sir David Brewster (1781-1868) in 1817. It consists of a tube with two mirrors placed at an angle so that the effect of multiple reflection is obtained. This produces a regular complex pattern of objects, typically pieces of coloured glas, placed at the base of the mirrors, which changes as the tube is rotates.