I'ri-scōpe, n.

n. [Gr. Ἶρις, rainbow, and σκοπεῖν, to see.] An instrument for exhibiting the colors of thin plates, consisting of a polished plate of black glass, on the surface of which, when prepared by smearing with soap and rubbing dry with chamois leather, a film of vapor is breathed, in which the colored rings are seen.