Kaleidoscope (kå-lī' dō-scōp), an ingenious and pleasing optical instrument invented by Brewster in 1817. In its simplest form it consists of a tube in which are placed two mirrors or reflecting planes so hinged together along one edge as to make an angle with each other which is an aliquot part of 180°; while one end of the tube is fitted up with an eye-glass, and at the other end are two glasses, between which are placed little fragments of colored glass or other objects which it is desired to examine. The eye, looking into the tube, perceives these objects reflected many times. There are various modifications of the kaleidoscope which increase its power. It is sometimes used by designers of patterns, to whom it furnishes an almost endless variety of figures.
