Show Zinc Causes Paint to Show Color Variation A mans man's puzzlement over a fencepost tepee fence post which he had hud painted black hinck but which turned white every night It was the starting point of ot a program of research research research re re- re- re search which has hns culminated In to the tile discovery of ot a number of chemicals having this remarkable chameleon like e prop property scientifically termed Information regarding these chemicals chemicals' has hus now been mode made I public by the American Chemical so so- clety The famous fence post was painted with a pigment having u a zinc basis It would turn black soon after atter sunrise each morning only to turn white again when darkness came Many explanations have been heen given for tor the phenomenon but U are not yet agreed as to the cause of ot It They have however found several sev sew eral other substances besides the zinc sulfide which was In the paint on the post that will also chan change e color with the lI light ht Must Most of 01 the known phototropic phototropic phototropic photo- photo tropic liquids are solutions of colorless colorless colorless color color- less d derivatives es of or certain dyes The solutions are practically colorless In Inthe Inthe the the dark but turn the color of of the parent dye de when exposed to light Actions Action n. n Alone Matter atter Jt It Is out not the mere station of ot life Ute that stamps the alu on us hut but tb manner manlier In we Poet fist our part part- I Schiller |