At Alabama Polytechnic Institute Professor Fred Allison early last year recognized eka-cesium, the 80th element in the Periodic Table (TIME, Feb. 17, 1930). Last week he had eka-iodine, the 88th and last unknown element.
His method was to take materials which he reasoned might contain eka-iodine. Since eka-iodine would be a halide like fluorine, chlorine, bromine and iodine, only heavier, he used seawater, fluorite and other halogen compounds. He burned each of them and sent their complex light through a polariscope and then through a magnetic field. A magnet twists polarized light to a calculable extent. The fineness of this magneto-optic rotation is such that it can detect one part of a substance in 100 billion parts. The greatest amount of eka-iodine Dr. Allison could find in any of his substances was one part in one billion. Eka-iodine is the rarest, most fugitive thing on earth.