COLOR MAGIC WITH POLARIZED LIGHT

By E. W. MURTFELDT
BLAZING with brilliant, ever-changing colors that rival the hues of the rainbow, the illuminated face of a giant electric clock is attracting crowds to an exhibit of timepieces at the San Francisco World's Fair. Visitors, curious to know how this spectacular effect is obtained, are amazed to learn that this gleaming disk of light, sparkling with an intricate, moving pattern of colorful stars and concentric circles, is produced not by any complicated arrangement of colored bulbs, projectors, and revolving niters, but merely by plain white light, and strips of transparent cellulose mending tape sandwiched between two practically colorless disks.