chromatrope

Century Dictionary and Cyclopedia

1. n. An arrangement in a magic lantern similar in its effect to the kaleidoscope. The pictures are produced by brilliant designs painted on two circular glasses, which are made to rotate in opposite directions by the turning of a crank.
2. n. A toy, consisting of a disk on which are painted circular arcs of bright colors in pairs, so placed that when the disk is made to revolve rapidly streams of color seem to flow to or from the center.
3. n. One of a group of acid coal-tar colors: as, chromalrope 2B, 6B, 8B, 10B, F, R, 2R, S, SB, and SR. They are all related to dihydroxynaphthalene-disulphonic acid, and dye wool bright red to violetcolors from an acid bath. They all give shades ranging from dark blue to black, when after-treated with potassium bichromate, and may therefore be classed as mordant-acid colors.

Wiktionary

1. n. An instrument for exhibiting certain chromatic effects of light by means of rapidly rotating disks of various colours.

GNU Webster's 1913

1. n. (Physics) An instrument for exhibiting certain chromatic effects of light (depending upon the persistence of vision and mixture of colors) by means of rapidly rotating disks variously colored.
2. n. A device in a magic lantern or stereopticon to produce kaleidoscopic effects.