Spinthariscope

Spin‐thar″i‐scope (?), n. [Gr. σπινθαρίσ spark + -scope.] A small instrument containing a minute particle of a radium compound mounted in front of a fluorescent screen and viewed with magnifying lenses. The tiny flashes produced by the continual bombardment of the screen by the α rays are thus rendered visible. — Spin‐thar′i‐scop″ic (#), a.