Willis Carrier (1876-1950), American developer of the formulae and equipment that made air conditioning possible. The 'Apparatus for Treating Air' (U.S. Patent 808897, granted in 1906), was the first of more than 80 patents awarded to Carrier and was awarded just five years after completing his engineering degree at Cornell University. In 1911, he described his basic Rational Psychrometric Formulae, which to this day is the basis of fundamental calculations for the air conditioning industry. He and six other engineers formed the Carrier Engineering Corporation in 1915, which stands today as the world's largest air conditioning corporation. In 1921, Carrier patented the centrifugal refrigeration machine used to condition large spaces. In 1928, he developed the first residential 'Weathermaker', an air conditioner for private home use.