chromatrope

from The Century Dictionary.

• noun 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.
• noun 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.
• noun One of a group of acid coal-tar colors: as, chromalrope 2B, 6B, 8B, 10B, F, R, 2R, S, SB, and SR.

from the GNU version of the Collaborative International Dictionary of English.

• noun (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.
• noun A device in a magic lantern or stereopticon to produce kaleidoscopic effects.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

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