The SciencesVersatile Eye-Testing Machine, Improved White Lead, and moreBy Alexander Klemin, F. D. McHugh on January 1, 1940AdvertisementABOUT THE AUTHOR(S)Recent Articles by Alexander KleminInstrumentation, Measurement, and ControlMust Flying be a "Racket"?Ideas in the AirRecent Articles by F. D. McHughCoal and Kilowatts, Carboloy Extrusion Process, and moreIndian Arrow Poison for Arthritis, Mental Disease, Enamels for Plastics, and moreGlycerine from Petroleum, Electrostatic Iron Ore Separator, and more