Kaleidoscope

Kaleidoscope (from Gr. kalos, 'beautiful,' eidos, 'image,' and skopeo, 'I see'), an optical instrument invented by Sir David Brewster in 1817. It consists, in its simplest form, of a tube, through whose whole length pass two mirrors or reflecting planes, which are hinged together along one edge, and make with each other an angle which is an aliquot part of 180°, whilst the one end is fitted up with an eyeglass, and the other is closed by two glasses, at a small distance from each other, between which are placed little fragments of glass or other variously-coloured objects. The eye looking into the tube now perceives these objects multiplied as many times as the angle which the reflecting planes make with each other is contained in the whole circumference of a circle, and always symmetrically disposed; and the slightest shaking of the instrument produces new figures. There are various modifications of the kaleidoscope, by some of which its power is much increased; for example the mirrors may be adjustable at various angles measured with respect to a variably distant centre, so that arched patterns may be obtained; and it is not only a pleasing toy, but is sometimes used by pattern-drawers and others, to whom it supplies endless varieties of figures.