The SciencesTractor for Comfort, Specialists Should Advise on Hearing Aids, and moreBy F. D. McHugh, Alexander Klemin, D. H. Killeffer on December 1, 1938AdvertisementABOUT THE AUTHOR(S)Recent 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 moreRecent Articles by Alexander KleminInstrumentation, Measurement, and ControlMust Flying be a "Racket"?Ideas in the AirRecent Articles by D. H. KillefferIndustrial ConsultantsThe Pilot Plant's Value to IndustryIndustry Gets Nosey